Soak the foot in Epsom salt every day for an hour. Try and pry the nail out of the flesh and cut it if possible. This should be started as soon as the first sign of pain is noticed.
Using nail trimmers, pull the ingrown nail portion out. Trim it off as straight as possible. Soak your toe in epsom salts and water. See a doctor if it's infected.
In the center of your toe, cut as deep of a V in your nail as you can without hurting yourself. The nail will naturally grow together, pulling it out of the sides.