There's no real clear cut answer to the creative process. Look at the Wire and YouTube, there are so many unique flourishes out there because everyone sees potential in something that no one else sees. I can guarantee that you'll find something no one else has made. If you haven't found something yet, keep trying or take a break and try again. You might find inspiration in something that you would never think of. You never know.
I made two flourishes based on odd ways of holding a deck. And I'm working on a third after watching salsa dancing tutorials.
But the key is that you need to have an idea, try, and be persistent. Just don't rush your creation. Take your time to perfect it.
I think at first you should know a certain amount of materials. And based on that, use your creativity to create new stuffs. Without basic things, it's very hard to develop. At least that's for me