Choose a bad font. What is a bad font? A bad font is unreadable. First and foremost, your goal is to make the text on your shirt readable in order to get your message across. Stay away from overly decorative fonts to the point where it feels like you have to decipher the letters every time you read it. Your font choice can make or break your design.
Use too many colors. One can always choose to use a lot of colors, and manage to still make a great design but if you’re a beginner, it’s best to create a cohesive color palette, and stick to it. Two to four colors will do. Restraint can force you to be a lot more creative, and yield better design.
Forget the purpose of the shirt. Keeping the purpose of the shirt in mind can guide and help you make better decisions when it comes to design. Always ask yourself what is the shirt for. Is it to spread awareness? Is it to persuade? Often, a shirt design can look good but feel totally misplaced. Try to align your design with the purpose of the shirt. After all, good design should be motivated.
Pick colors that are low in contrast. The best way to make your design pop is to utilize colors with high contrast. Don’t use too many muted colors at the same time; try to pick a darker color or a brighter color to balance it out. Designs with higher contrast improve readability and provide greater interest.
Export your design in HD. This may be already common sense to some. However, it is such a common mistake that it needs to be included in this list. A lot of people end up with pixelated designs on their shirts, sending all their hard work down the drain.
Skip creating a mockup or sample layout. Deciding on the design’s juxtaposition on the shirt is still part of the design process. Don’t get too excited, and skip to getting your shirt design printed. Take time to create a mockup of your shirt (or, download easy-to-use mockups from the internet) to make sure that you and the printing service provider are on the same page.
Steal other artists’ work. Never ever do this especially if you intend on making profit from your design. Not much has to be said about this; the bottom line is that it’s wrong. Most of these aren’t rigid rules but they are simply guides for designing shirts. Don’t be afraid to break any of them (except the last one, obviously). Get creative!