I'll have to answer this in a series of blog posts, as each design is very different. They all have one thing in common: lots of playing and experimentation in Procreate, Photoshop, and Illustrator. I'll frequently begin with one of my old photographs and select color schemes, shapes, and ideas from those images.
The design you see in Gigi's wild rag scarf (see my first blog) started in Procreate as the doodle you see above. Just a doodle. I was simply playing, and after a few days, some sections stood out as being interesting on their own. I selected those sections and played more in Photoshop and finally took everything to Illustrator for vectorizing (I'll explain that in a different post).
The most important creative step I take is to dismiss any notion that my designs aren't interesting, or that I shouldn't proceed. By removing all negative thoughts in my mind, I give myself permission to create, play, change my mind, toss out, renew, and revive designs. The patterns you see at my Spoonflower store are results of that creative process.