Row 2: double crochet in the second chain from the hook and continue across (3 double crochet), chain one.
Row 3: double crochet in the second from the hook and continue across (3 double crochet), chain one .
Row 4: double crochet in the second from the hook, then to increase do two double crochet in the next chain, then continue double crochet across (should now have four double crochet across). Chain one.
Row 5: double crochet in the second chain from hook, do two double crochet in the next chain then continue double crochet across (should now have five double crochet across). Chain one.
I continue this increasing one in a row until I get the desired width which for me is usually just under 4 inches. Note: I do not increase in every row, here and there I leave a couple rows the same width. After I get the desired width I continue to add rows until I hit the halfway point which is 9 and 1/2 inches. I put a short piece of yarn there as a marker to mark the halfway point. I continue to double crochet the same width across for as many rows as I did on the first half, periodically folding it over to compare to first half to make sure I am still on track. When you get to a row where on the first half you increased it is time to decrease on the second half. Here is a great tutorial on decreasing stitches, it is for single crochet but same idea applies. http://www.youtube.com/watch?v=Ahd2xwWi-F4 Continue until second half matches first half. On the second from last row to make the hole for the button, double crochet in the second chain from the hook, chain 1, skip a chain and double crochet into last chain in row (so you should have a double crochet a chain and a double crochet), chain one. For last row double crochet in the second chain from hook, double crochet around the middle chain, double crochet into last double crochet (should have 3 double crochet). Cut the yarn and join with the yarn that you will use for your trim (unless you are using the same color). For the trim just double or single crochet around the headband until you get to your starting point and join both ends of the trim (I use a slip stitch), cut the yarn, tie it off and work the excess back in. Lastly attach the button of choice, I use yarn but some use thread.
Sorry I do not have a more exact pattern but like I said if there is interest I will try to write it down and take pictures the next time I do it.
In the second chain from the hook you are going to double crochet 7 into one chain. Start out by double crocheting one really tight, chain one, the second double crochet a little looser making it slightly higher than the first, chain one, the third double crochet a little looser than the second making it slightly higher, chain one, your fourth will be your loosest and highest double crochet, chain one, the fifth double crochet a little tighter than the fourth (should be about same as third), chain one, the sixth double crochet a little tighter than the fifth, chain one, the seventh double crochet tight, chain one. Should look like picture on left.
In the next chain (if you cannot get into next chain skip a chain, I do not like to but sometimes have to) repeat steps for first petal including slip stitch at end. Continue to do this until you have about 15 or 16 petals.
Should look something like this and yes will be all twisted if left on its own, this is normal. Do not cut it and tie it off until you check to see how it looks put together. Sometimes if there are too many or too few petals it looks a little lopsided, I usually coil it around periodically starting after petal 13. When you have the desired amount of petals go ahead and cut the yarn and tie it off.
Last step is to place flower at desired location on headband, cut about a 25 inch piece of yarn. Work yarn in and out of headband and bottom of flower from underneath headband until you are satisfied it is securely attached. Tie off yarn and cut excess yarn. And you are done!!
Hope this helps!