How fun! Well I don’t know your background, but from your user name I gather you already make and sell items…but I could be jumping the gun.
If you don’t design yet, I would highly suggest you make sure you have a graphics design program that can work with SVG and learn that program inside and out…I just changed to another program (other version didn’t work well) and so I am having to watch videos to learn it…slowing me down tremendously. I’ll make progress soon, I just had to stop GF stuff and work on making masks for my family. 
so many ideas, so little time… I’d also suggest reading the Tips & Tricks section:
Welcome!