My name is Lilith, I'm on the Social Care team at Shopify.
That's exciting to hear about your print on demand store! Creating designs is a ton of fun, but you'll want to be sure you have the right tools to make them look amazing. I'm glad that you're looking to do more than just words, this would set you apart from a lot of other print on demand businesses.
Quick Tip: Make sure that your designs are saved in PNG format and are at least 300 DPI so your designs print out in high quality.
Below are some of my favorite web apps, software, and mobile apps that can help you get some really great looking designs that are more than just the blocky font words.
This was just an extra resource that I wanted to include. If you've got a great eye for design and can whip up a few designs over the weekend, that's awesome! However, if you're not too comfortable with designing or if you don't have a lot of experience in it, you can also have someone create a set of designs for you as well.
However, you can also choose external freelancers as well. Here are a couple of other sites that you can find some freelancers for any of your design projects:
Let me know how you do with the information above! I'm happy to answer any questions you think of as you work on your business.