This is a pretty easy project that just requires a LOT of dry time.
I like neat socks, but I don't like the way my feet slide around on the kitchen floor when I'm not wearing shoes. This is a quick fix to a favorite pair of socks that you only wear around the house.
Put your socks on a flat surface. You will want to lay them out in such a way that the entire bottom of the foot is facing you.
Shake your fabric paint well. Paint your design on the bottom of your socks (work on one at a time so you don't risk smearing the paint). You will want to keep the paint puffy or it might not grip well.
Let your socks dry for a few hours. To help speed the drying process, you can use a hair dryer on high/hot. It's a good idea to allow for a full drying period before wearing them.
After they're totally dry, try them out!