Compost is one of nature's best mulches and soil amendments.  It is much better than commercial fertilizers that leaves soil hard-panned or sterile of mico-ororganisms.  Compost improves soil structure, texture, and aeration and increases the soil's water-holding capacity. Compost loosens clay soils and helps sandy soils retain water.  Compost improves soil fertility and stimulates healthy root development in plants. As soil improves, the soil improves even more with worms moving in to aerate and fertilize the soil with their castings.

Collect material in the fall for ready compost in the spring.   Gathering the abundance of spent plants in the fall for composting over the winter will ensure a ready compost supply for emerging hungry plants when the weather warms.  If done in the spring, compost material will not be ready for another few more months.  In addition, fall material will have lost a lot of nutrients by the spring.

Be patient about composting results. Do not expect finished compost in a few days as hyped in advertisements, especially during the cold winter months. Decomposition takes time. Even if the material looks like compost after several weeks, it still requires an additonal one-month maturation peiord before applying directly to plants. Otherwise, the composting unfinished material will draw nutrients away from the plants. The venerable Rodale Institute that started the whole organic gardening and farming movement has a great course about soils and composts Rodale Institute Course Soils that you should check out for a good understanding of how compost works. Rodale has been passionate organic advocates since 1947 way before its current popularity. Mother Earth News http://www.motherearthnews.com/search.aspx?search=compost. provides good down-to-earth information and studies to help you through the advertising hype.

Do not get overly scientific about composting, especially with the many arcane charts, tables, and studies abounding on the Internet about the 25 or 30 or 40 to 1 carbon-to-nitrogen ratio. Composting is not complicated. Composting thrives when different types of material are mixed together with air and moisture. While ratios are fine for compost hobbyists, regular gardeners need only remember that all organic materials will compost in time given some prudent attention.

That is not to say that the carbon-to-nitrogen ratio is not important. You should try to maintain a balance, not mostly all carbon (all brown leaves!) and not mostly all nitrogen material (all green grass clippings!).  A chart of material is useful for helping those starting off in composting to choose materials until they have a good feel for it.   Below is a chart from the authoritative Rodale Book of Composting showing the carbon to nitrogen ratio of some material.  The book has more extensive lists of materials beyond this chart.  The chart shows that higher carbon content will tend to be associated with spent, drier, coarser  material (commonly referred to as "browns" for good reason) and higher nitrogen content associated with fresher, wetter material (commonly referred to as "greens").

A recommended rule of thumb that will get you close to a good carbon-nitrogen ratio when starting a mix of material is 3 parts of brown to 1 part greens (ratio attributed to the father of composting Sir Albert Howard). Be sure to throw in a handful or shovelful of dirt or compost into the material mix to activate the composting process (else you will be waiting a long time for something to happen).