The absolute best thing that you can do to increase your supply quickly is nurse more often. I see from a previous post that you have started your baby on solids. Always always nurse first, then give baby food. Your milk is your child's nutrition, and baby food is just for fun. Nurse your baby before every meal, so that he's always coming to you hungry.
If your baby is starting to sleep through the night, or if he sleeps later than you do in the morning, you can add a pumping session to your schedule first thing in the morning. That can help some - but remember that a pump does not replace a baby (as far as your body is concerned), and you shouldn't pump instead of nursing, you should add a pumping session in addition to adding nursing sessions.
While you do this, make sure you are hydrated.
There are other things out there that claim they help - for example, oatmeal is supposed to help and there are recipes online for mother's milk oatmeal cookies, and there are teas marketed to this, etc. But I never found anything to really work except for increasing the frequency of nursing. Milk production is mostly about supply and demand - the more your baby demands it by nursing, the more your body will make.
Good luck.