The first rule of thumb in composting is to get the carbon:nitrogen ratio right in your bin. Carbon helps to break down organic material, and nitrogen helps to rebuild cells. Too much of either and you'll be holding out for lovely soil that will never be. Secondly, compost almost anything organic except dairy, meats, oils, and other fats. Here's a quick guide to good sources of carbon and nitrogen:
Carbon: dead leaves, strips of paper, cardboard, sawdust
Nitrogen: food scraps(!!), coffee grinds, grass clippings, urine
Now I've read about people who urinate all over their lawns and gardens, but I don't think I'll be peeing on my porch anytime soon. Google 'composting ingredients' for a more complete list of what can be composted. Depending on what's in your bin will determine how fast your organic waste turns into a verdant pile of beautiful, rich soil..for free! (Last weekend I bought a bag of soil no more than 5lbs for 40 pesos!) For example, throw a load of human or pet hair and you will be staring at that same hair for awhile. I'm off to find the perfect bin...