
Composting
What can I say about compost that hasn't been said before? Not only is it one of the easiest ways to remove a significant portion of your waste stream from landfills, but it pays for itself in the form of nutrient-rich soil that can be used to grow more food.
I've had excellent luck with all types of composters, both the standard bin type and the rotating type. I currently have an Envirocycle, which is compact and sits atop a set of rollers that make turning it a breeze (assuming you're rocking some guns under your shirt).

What To Add
Anything plant-based! Vegetable and fruit peels, egg shells, coffee grounds, compostable take-out containers.
What NOT To Add
Most things animal based. Meat, fat, cat and dog poop, bones, and other things that won't break down cleanly should be thrown away instead.

Maintenance
A compost pile is a living ecosystem. Luckily for us, nature has some pretty cool technology at its disposal. Insects, fungi, and other organisms we rely on are largely self-correcting and will still decompose things under non-optimal conditions. If you want your compost fast, though, there are a few things you can do to speed it up.
You can get as technical as you like, but if you're throwing in nothing but fruits and vegetables, you're going to end up with a smelly pile that just sits there. Add bits of dry leaves, straw, or untreated cardboard—grocery bags and toilet paper tubes work well. Avoid waxed or treated cardboard, and be sure to remove any tape.
When a compost pile's oxygen content falls below 10%, some of the organisms switch over to anaerobic breakdown, producing methane (a greenhouse gas) and hydrogen sulfide (smells like rotten eggs). Turning your compost is the easiest way to add oxygen to large piles, and is especially important if you are composting a lot of nitrogen-rich materials like fresh grass clippings. Turning composters like the EnviroCycle take the hassle out of this chore.
Keep it growing!
My experience has been that once I fill my composter to a certain level, it hits a steady-state in which the microbes break down things as fast as I can add them. Remember, you've created an entire universe within your composter. Keep it happy!