water is usually a big think, but I actually drink TONS of water. Cutting down on calcium can help, drinking OJ can help, NOT drinking soda can help, eat lots of fruit, stay away from tea but you should drink lemonade. Also, lots of spinach can cause them as well. Too much vitamin C can actually cause them as well.
I'm pretty young to get them (25) and i gotta piss it out to have it analyzed. There are 5 main types, and once you find out what type it is and what it is made of you can better understand what you need to cut back on.