Maintaining an ideal carbon to nitrogen ratio is key number one... I add to our compost pile(s) year-round: 5~10 gallons of kitchen scraps, then chicken manure from the coop of a couple dozen chickens, and topped off with a good amount of straw bedding...
Our Winters, here on the Oregon coast, are very very wet... I use old cranberry crates to house the compost piles... During the rainy Winter months, it is loosely covered with a piece of plywood or similar: for reasons previously mentioned. This keeps the microbes and worms happy
