for now you get these incredibly bad cellphone pictures. I don't understand what causes that line/brightness/color difference. Boo.

scissors

fabric (I used 2 layers of cotton, cut in a circle or something like a circle)

nice strong thread and a good sharp strong needle

stitch around the edges, then gather

fill with batting and pull the thread tight and reinforce the stitches

I like to make an indent on the bottom. you can keep it or cut it later (knead the ball the string ends disappear)

I like to try and make them as tight as possible. Maybe similar to truing a wheel, making it as even and tight all around.
I made another smaller less filled yoyo ball thing, attached it to the larger one then sewed pearls all around where they meet. (the needle I was using was about the same size if not larger than the space in the beads, so the pliers were needed) After attaching the pearls I put some acrylic glaze on the pearls and string there and let it dry.
HERE IT IS. Crummy picture, but awesome dense pin cushion.