Make sure all the products you do use including moisturizers, sunscreens and make-up is OIL free. You can also try oil absorbing sheets (Clean and clear makes them, and some other brands). You just blot these on your face when its feeling oily or shiny and it sucks the oil right up without removing makeup.
There isn't really anything you can do to stop oil production on the skin, everyone is different. the amount of oil can also be related to your hormone levels. Sometimes starting a hormonal birth control pill can regulate your hormones and create less oil which you could try if the oil is giving you acne.
Other than that drink lots of water.

I already do drink a ton of water and the stuff I use on my face doesn't have oil. I'm very careful about that.

Do the blotting sheets work better than just plain tissues or paper towels?