Step 1: Layout of the main part of the cap
1. Measure around your head where you want the cap's bottom to be. Write this down somewhere you can get to it later because if you ever want to make more hats you'll appreciate not having to remeasure. For my hats I normally create one strip of fabric 23" long by 5.5" tall (I wear a size Small-Medium hat normally).
2. Using a ruler and a marker or pencil mark your cutting lines on the fabric
3. Cut out the strip(s) of fabric (in my case I made 3 pieces: two 10"x5.5" and one 4"x5.5" but normally I would only make one 23"x5.5" strip)