One thing I’d like to learn how to do better is make mock-ups outside of Spoonflower’s defaults (which are mostly home decor). I’d love to show people what they can do with fabric. I spent a little while poking around, and these free templates are an example.
I don’t have Photoshop, but you can use a site called Photopea to work with these PSD templates for free, and a YouTube tutorial made the process very simple.
I still have a lot to learn — for one thing, I’d like to scale these to much smaller scale — I’m guessing I need to do that in Procreate directly and save the PNG files, before making the mock-ups? Though if there’s a way to do it in Photopea, that would be better. Things to figure out…
But even in large-scale, that baby swaddle is cute. 
Free mock-ups via #TheIndoorsyProject!
