Mixing roughly equal volumes of fresh "greens" (grass clippings, fresh weeds and flowers, etc. – higher in nitrogen) and dried "browns" (straw, corn stalks, fall leaves, etc. – higher in carbon) provides a good C:N balance. Experiment to find a recipe that works for you, or check a composting book for tables showing the C:N ratios of different materials. 30:1 is an ideal mix for fast composting.