Whether you’re an experienced interior designer keeping your skills sharp or a passionate DIYer tackling your next home project, a solid understanding of design rules will help streamline your approach and elevate your results.
This industry is filled with principles that have stood the test of time. Other rules continue to evolve alongside fresh trends, changing lifestyles, and new technologies. Below, we’ll walk you through evergreen concepts like balance and proportion, as well as modern must-knows like layered lighting and negative space.
These foundational design rules are here to guide, not limit. As you read through, consider how each one fits into your current approach—and where there’s room to stretch your style or rethink your process. Some may already be second nature; others might inspire a small shift that makes a big impact.
Table of Contents
1. Follow the 60-30-10 color rule
The 60-30-10 color rule is one of the most timeless principles in interior design. It’s a simple, effective way to build a balanced color scheme that works across styles and spaces. And it doesn’t just apply to wall color—it also extends to furniture, textiles, and decor. Here’s how it breaks down:
- 60% of the room should be a dominant color. Think walls, large furniture pieces, and area rugs.
- 30% of the room should be your secondary color, which supports the dominant hue but also adds contrast. This could include drapery or accent chairs.
- 10% is your accent color, which should be saved for accessories like throw pillows, vases, and artwork.
While bold palettes and color-drenched interiors have been trending in recent years, the 60-30-10 rule remains a reliable starting point—especially for DIYers or newer interior designers unsure of where to begin. Its timeless nature makes it more enduring than fleeting color trends.
This example prioritizes a rich brown taupe color, weaving in black, blue, and gold.
2. Decorate in groups of three
The rule of three is a staple across interior styles, from minimalist to eclectic. It’s rooted in the idea that odd numbers are more visually appealing and feel more natural to the eye than even numbers. This approach also helps styling look intentional. While it’s commonly called the “rule of three,” it really refers to the broader “odd number rule”—you’ll often see designers use groupings of 3, 5, or 7.
- Group items like candles or vases in sets of three (or other odd numbers).
- Vary the height, shape, and texture of grouped elements to add dimension.
- You can also apply this rule to large areas and statement pieces, such as furniture, throw pillows, and wall decor.
Check out this example with three vases of different shapes:
3. Every room needs a focal point
Every well-designed room needs a focal point—a visual anchor that draws the eye and sets the tone for the space. While fireplaces and TVs are common choices, focal points can also be a striking piece of art, a sculptural light fixture, or a window framing a scenic view.
- Choose one strong focal point per room to avoid visual clutter.
- Arrange furniture and lighting to highlight and support the focal point, guiding attention exactly where you want it.
- Use contrast, scale, or color for emphasis.
In this example, original art makes for the perfect focal point
4. Lighting should be layered
Lighting schemes are central to great design. Layered lighting creates functionality, mood, and depth. Here are the key types of lighting to incorporate when building a layered lighting scheme.
- Ambient lighting: Your main light source (ceiling lights, chandeliers, etc.).
- Task lighting: For specific activities like reading, cooking, or working (desk lamps or under-cabinet lights).
- Accent lighting: Used to highlight artwork or architectural features (wall sconces or picture lights).
Tip: Think of lighting as a compilation. A single ceiling fixture isn’t enough. Layering light sources adds visual interest and allows you to adapt the space throughout the day and night.
In this example, we see soft overhead lighting and wall sconces:
5. Maintain balance and proportion
Balance and proportion are essential elements of good design. As spaces become more flexible and multifunctional, these principles help maintain harmony.
- Symmetrical balance: Formal and traditional; mirroring elements across a central axis.
- Asymmetrical balance: More casual and dynamic; different elements balanced by visual weight.
- Proportion: The relationship between objects and the space they occupy. Oversized furniture in a small room feels cramped, while tiny decor in a large space gets lost.
Balance starts with scale, but it doesn’t end there. Great designs also depend on elements like color distribution and material contrast. Paying equal attention to these cues ensures a space isn’t dominated by a single hue or lacking in tactile variety.
This example showcases two stunning rooms that approach balance in different ways, with the first showing two chairs on either side of the fire place and the second showing two chairs balanced out by a sofa:
6. Make negative space work for you
In a world filled with stuff, negative space feels like a breath of fresh air. Also known as white space, this term refers to the empty areas around and between objects. Emphasizing this negative space is key when creating clean and spacious environments.
- Let furniture and decor breathe. Don’t overfill every wall or surface.
- Use negative space to highlight a statement piece or architectural detail.
- Don’t think of negative space as wasted space. It helps the eye rest and the room feel open.
Note: This principle is especially useful in modern interiors, but it can benefit all design styles.
This carousel showcases a few examples and corresponding benefits of negative space used right:
7. Use symmetry strategically
Symmetry can make a space feel harmonious, balanced, and intentionally designed. When used thoughtfully, it introduces a sense of order and calm.
- In formal areas like dining rooms, entryways, and living rooms, symmetrical layouts often work best.
- Mirror furniture, lighting, and decor on either side of a central anchor (like a fireplace or bed).
- In more casual or contemporary spaces, opt for near symmetry—such as two different chairs with similar visual weight or color.
Tip: While symmetry provides structure, too much of it can feel rigid. Break things up with organic textures, natural materials, or asymmetrical accessories to keep the design feeling fresh and inviting.
This example showcases symmetry in the windows, window treatments, and dining table placement, while assymetrical lighting adds a touch of whimsy:
8. Incorporate contrast and texture
Color is often the first thing people notice when entering a room, but don’t forget texture and contrast. They give a space depth and character, and are essential for making spaces feel complete.
- Mix smooth and rough textures: velvet and rattan, matte and glossy finishes, metal and wood furnishings.
- Combine light and dark elements to create contrast.
- Pair sleek, modern finishes with a variety of tactile materials to add warmth.
Remember: Texture and contrast don’t require excess, just intention. Even in minimal spaces, a thoughtful mix of materials adds depth without overwhelming the design.
Here’s an example from Nikki Levy, who’s known for blending very different textures:
9. Let function drive form
This age-old principle is especially important with the rise of multifunctional spaces. Design should always serve the way the homeowner lives—not the other way around.
- Choose furniture based on lifestyle needs (entertaining, remote work, family activities, etc.).
- Prioritize flow and comfort over trends.
- Ensure even the most beautiful rooms are livable and practical.
Note: Whether you’re designing a studio apartment or a large family home, ask yourself: Will this layout make my client’s daily life easier? If not, it may be time to rethink the design.
This example shows a yacht-watching corner, where every design choice is intended to support watching boats go by outside:
10. Personalization, not perfection
Remember to make each design its own. Interiors aren’t about copying magazine spreads or mimicking influencers. The most impactful rooms simply reflect the people who live in them.
- Display personal collections or travel souvenirs.
- Choose colors that match the homeowner’s personality, not just current trends.
- Incorporate meaningful handmade and vintage pieces.
Remember: Design rules provide a roadmap, but the final destination should always reflect the homeowner’s style and story.
This example showcases European flair and retro elements, for just the right level of clutter and sophistication:
11. Create cohesion with repetition
Repetition is a powerful design strategy that can help unify a space and guide the eye. When used thoughtfully, it can help your work feel purposeful instead of random.
- Repeat colors, shapes, patterns, or materials throughout a room (or across multiple rooms).
- Repetition doesn’t mean duplication—vary scale or texture to keep things interesting.
In this example, we see repeated colors of blue and yellow as well as repeated flower motifs:
12. Make room flow a priority
Designing with flow ensures that people can move naturally and comfortably through a space. It’s another sentiment that these spaces are being designed for use, not just for style.
- Avoid overcrowding pathways or placing furniture too close together.
- Think about how people enter, exit, and interact with the room.
- A room with good flow feels intuitive and relaxed.
In this example, we see a home that is a bit cluttered and maximalist, but the open space and room flow make it all work seamlessly:
13. Always maximize your sightlines
Great design considers both the details up close and the bigger picture. Clear, intentional sightlines can make a space feel more open, connected, and expansive.
- Create clean, intentional sightlines from one area to another.
- Avoid blocking windows or visual connections between rooms.
- Use statement pieces to guide the eye and create depth.
In this example, we see nice open sightlines from the kitchen to the living room:
14. Tech should be seamless
Smart homes are here to stay, but the key is subtlety. Integrating technology into your space shouldn’t disrupt the design, but quietly enhance it.
- Hide wires and tech components in cabinetry or behind furniture.
- Choose tech that blends with the room’s aesthetic.
- Design spaces that support smart living without sacrificing style.
Swipe through this carousel to see multiple examples of how Lobo Studio uses technology to create immersive design experiences.
15. Always measure twice
Tradesmen have long been advised to measure their work twice before cutting, and the same rings true for interior designers. Small measurement errors can lead to big headaches. A little extra caution goes a long way, and can save you time, money, and frustration down the line.
- Measure doorways, hallways, and staircases before ordering large furniture.
- Double-check wall dimensions before hanging art or shelves.
- Keep a tape measure or digital measuring tool handy during planning.
Note: While this is a practical rule, it’s just as critical as style-based guidelines.
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Interior design rules FAQs
Frequently asked questions about interior design rules.
Interior design is both an art and a science, so not every rule is set in stone. You don’t need permission to break the rules when it feels right. Some rules that can often be broken include the 60-30-10 color rule and symmetry, since these depend heavily on personal taste and the vibe you want to create. For example, mixing unexpected colors or using asymmetry can add character and energy to a space. The key is knowing why you’re breaking a rule and doing so intentionally to support your design goals rather than accidentally creating chaos.
Some rules are less flexible because they affect comfort, function, and flow. For instance, always measuring twice before purchasing or placing furniture saves time and money and prevents frustration. Stylistic rules that are almost always important include layered lighting, negative space, and balance/proportion. For more information on important design guidelines, check out our blog on interior design principles.
Understanding the purpose behind a design rule is the first step. When you fully grasp why a rule exists—whether it’s for visual balance, function, or harmony—you can better decide when it makes sense to bend or break it. Experimentation is encouraged, especially if you want your space to feel unique or personalized. Just make sure the result still feels intentional and livable.
Absolutely. Interior design rules serve as a foundation to build upon, but personal style and lifestyle needs should always be the priority. Design should reflect who the homeowner is and how they live. For example, if they love bold patterns or unconventional layouts, you can integrate those elements thoughtfully while still respecting key principles like balance and flow.
Whether you’re designing your first space or your fiftieth, these foundational rules will help you create interiors that are beautiful and balanced. And remember—great design isn’t about following every rule to the letter. It’s about knowing which ones serve your space, and having the confidence to bend or break the rest.
If you’re looking for more resources to enhance your design process, check out our guides on interior design abbreviations, styles and trends today. While they don’t offer strict rules, they might provide the creative spark you need to confidently ditch a principle on this list.
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