I made this for my mom :)
Ok, all you do is start with a basic crocheted circle pattern until it is wide enough for your head, then stop increasing.
row of single, row of half double, row of triple, row of half double, row of single, row of half double...you get the point. When it is just covering the tips of your ears, start the band, which was just a row of double, a row of half double and a row of double. Then switch back to your first colour, do a row of half double. Turn the hat "inside out" and crochet around (you should be going backwards compared to what you were doing) in a half double row. Cast off.
Make whatever flower pattern you desire and use your darning needle to put it on with some leftover yarn. Put on a button if it tickles you :)