The quicker you treat the stain, the better
Baking Soda - Sweat, food, grease
Vinegar - Coffee, wine, tea
Peroxide - Blood. Peroxide is a good bleach alternative.
Alcohol - Breaks down grease in food stains and things like slime.
Dawn - Everything, but especially food stains and grease stains from things like chapstick left in pockets.
Tide - Everything from grass stains to food stains.
Do not dry if the stain is still visible - repeat the process as needed.
Some grease, oil, food, and especiall chapstick stains are better left overnight with Dawn dishsoap.
Always try to test and area of the fabric that isn't visible, like an insole pocket or seam, for unwanted bleeding or discoloration.