One of the keys to composting is aeration. The bacteria need oxygen to carry out the aerobic respiration that creates rich compost. One way to aerate your compost is with a pitchfork or a compost turning tool. If you keep your compost in a tumbler, however, all you have to do is turn the container. Since most compost barrels can be expensive, you may be interested in building your own for much less money and an hour of your time.
Follow the photo-link to find the instructions for building your own.