My compost is at a standstill. What do I add?

If you have a relatively good mix of greens and browns, it should respond with aeration (like tossing a salad), water till moist, and a little molasses to feed the microbes. If you have a lot of woody material it will take a long time.
Tony M

The pile needs a proper ratio of carbon-rich materials, or "browns," and nitrogen-rich materials, or "greens." Among the brown materials are dried leaves, straw, and wood chips. Nitrogen materials are fresh or green, such as grass clippings and kitchen scraps.

Mixing certain types of materials or changing the proportions can make a difference in the rate of decomposition. Achieving the best mix is more an art gained through experience than an exact science. The ideal ratio approaches 25 parts browns to 1 part greens. Judge the amounts roughly equal by weight. Too much carbon will cause the pile to break down too slowly, while too much nitrogen can cause odor. The carbon provides energy for the microbes, and the nitrogen provides protein.

Couldn't have said it better. While my pile just sits there and goes quietly about its business, it always seems to respond to a good turning. And as an added bonus, you get to smell the sweet fragrance of the finished compost.