This is a sewing tip. I have a special foot for my sewing machine for sewing on buttons. I love it because it's such a time saver. Anyway my tip is this: before I sew the button on, I lay a flat toothpick on top of the button and hold it there until I lower my presser foot. I sew over the toothpick so that when I wear the item the button doesn't "pucker" the fabric. It makes the button just loose enough to prevent the puckering.
PS: You may need to hold the toothpick still while sewing the button on.
The toothpick is a nice idea! Also, for those who don't have the special foot, what I do is to take the foot right off my machine, then find the zig-zag width that is right for the 2 holes on the button. I simply hold the button/fabric in place, and use my other hand to spin the flywheel (so it doesn't go too fast).
Also, when I am done, I like to pull the threads through to between the fabric and the button, and wind the ends around the other thread, like a wound-shank button, before knotting them. Sure beats sewing buttons on by hand!