You must make sure your feet are totally dry before putting on socks and shoes. I use an old clean t-shirt to dry each toe, then I let my feet airdry for at least 15 minutes before putting any shoes on. Also, make sure you are wearing only cotton socks, anything with polyester or other synthetic will cause the problem.

I have heard that soaking them in tea tree oil helps.

Below is a link I found, I would also Google "athlete's foot remedies" to help you find others.