These can be made in different sizes- I made them from paper strips from 1" to 2.5"- though the larger ones need two strips of paper glued together. All you need is paper (I use heavier cardstock), hole punch, adhesive and a glue gun.
First cut your strip of paper- this one is 1.5" (which makes a 3.5" diameter flower). You will also need two circles (not shown) to cover the center- I used 1" circles for this one.
After you get your paper folded, smooth it out a little bit and punch holes down one side (not on the folds). I used my tiniest hole punch for this and it really doesn't matter if the holes aren't perfectly straight- you won't be able to tell once it is finished.