Color is an important element of design, and a crucial part of graphic design. The way we see things can be influenced by our environment, and our perception of what’s “real” or “normal.” Color theory is about how colors work together in relation to each other. It’s not just about picking out a few colors to add to your next project — it’s also about understanding why you’re making those choices.

A lot of designers have their own unique methods for choosing colors, but there are some basic rules that apply universally. Here are five rules to keep in mind when comparing colors.

1) Choose colors that complement one another.

When you’re trying to pick complementary colors, you want to look at two different hues that are opposite on the color wheel. So if you were looking at blue and orange, the blue would go with the reds, greens, or pinks. And the orange would go with blues, purples, or light yellows.

You may think that this sounds obvious, but I’ve seen plenty of designers who use these opposites as inspiration without really considering the effect they’ll have on their clients’ eyes. You don’t need to pair every hue with every other hue, but doing so will help your designs pop more than they might otherwise.

2) Don’t make all the colors too similar.

If you have three colors that are very similar to one another, the eye doesn’t have much room to differentiate between them. So instead of being able to distinguish one from another, they blend into a single color, which makes it harder to tell where one ends and another begins.

The best approach here is to consider how many different tones you want to include in your palette. If you only plan to use four colors, then you don’t need to worry about this as much. But if you’re planning to mix a lot of colors, then you should try to avoid including too many shades that are nearly identical to one another.

3) Use warm colors for backgrounds.

Warm colors like yellow, red, and orange are great for creating contrast against cooler colors like blue and green. They also create a sense of energy and warmth, which is good for inspiring people to feel positive emotions. Conversely, cool colors like blue and green tend to calm people down.

4) Try to match up the colors used in your logo with those used in your website.

This isn’t necessarily true for logos, but it’s a good idea to get your branding consistent throughout your various online media. For example, if you use a certain shade of blue as your company’s logo, then it’s probably a safe bet to assume that you’ll choose that same shade of blue for your site as well.

5) Pay attention to the dominant colors on your client’s brand.

It might seem like a no-brainer, but sometimes it’s easy to forget the most important thing when designing for others: what they already know. If your client has a brand identity that includes primary colors, then you should follow suit. These hues are typically associated with excitement, joy, and happiness, and they can give your work a nice boost of personality.

But if your client has a brand identity that uses muted colors, then you shouldn’t force yourself to do the same. Muted colors are often considered more professional, and they’re less likely to cause your viewers to feel uncomfortable.

There are plenty of other ways to approach color selection, but these five guidelines should prove useful enough to get you started. Before you begin any project, take a moment to review these five rules, and see whether or not they apply to your particular situation. Then, when you find yourself stuck in a creative rut, these simple tips should come in handy.

In addition to these basics, you’ll want to familiarize yourself with a number of other color theories. And finally, you should pay attention to the color psychology of your target audience. What colors do they prefer? Which ones do you feel comfortable using?

And finally, remember that color is not the only one aspect of design, and that you should always strive to achieve harmony across multiple elements.