I recently learned about traditional Japanese hair accessories called kanzashi. They can be made from a variety materials but fabric kanzashi have become quite popular. They are simple to make and can be created from a variety of leftover materials. This is the one I made yesterday.
The center is usually covered with a button or something which covers the edges of the fabric that are gathered there. I used one of the few buttons I could find. Somewhere I have a stash of them. I think fabric covered buttons or neat jeweled buttons may be the way to go.
To learn this technique, I watched this first video from Jensmum which shows the petal creation process. She pins them. When I made mine, I pinned them then used a sewing needle to thread them together. After that, I snipped off some of the "wrong end" close to the threading. After that I pulled them together, as on this second video from Jensmum (found on YouTube). This page by craftgrrl shows the process in a series of pictures, including snipping off the tails. Also, Jenifer Minnis has a recipe for rice paste which is traditionally used to hold kanzashi together. Rice paste is simple to make and dries hard and clear.