If you are just starting to compost, it helps to keep a list handy of what can, and shouldn't, go into your compost pile.
First, decide on what kind of compost you are going to make. If you are setting up a compost with fencing outside, where anyone can access it, you won't want to include some materials.
Some lists say you can't compost meat, fat, bones, dairy and grease because those will attract wild animals. If you have a closed composter with a lid you can securely close, you should be able to include those.
Almost everything else is also fair game, including dryer lint as well as pet hair but I am getting ahead of myself.
Compost is basically decomposed organic matter that can get "cooked" to quickly return organic matter into soil, called hot compost. It can also be left to slowly decompose over a year, or two, like oak leaves in my ditches, which is considered cold compost.
I need to amend what little soil I have on my limestone hill garden so I try to "cook" in my composters as often as I can. I also keep an eye out for any garden areas that have naturally turned organic matter into the dry, dark, crumbly "black gold" that fortifies and enriches our packed, clay-based soil.
Compost is often mistaken for fertilizer and applied right before planting. Think of compost more as a meal for living soil microorganisms. It's best to add compost in fall, which gives microorganisms time to absorb compost nutrients before you plant in spring.
There are a number of detailed recipes available that give specific carbon (brown) to nitrogen (green) ratios. Frankly it doesn't have to be that complicated. I basically add one part brown, such as dried leaves, to one part water and one and half parts green. I toss a measure of soil and manure in every once in awhile and, as long as it is mixed every 3-4 days or so and seems to be changing, it usually breaks down within 4-6 weeks.
If your compost has a rotten rather than rich, earthy smell, add more brown materials and make sure to stir it well to mix in oxygen. That will help reduce odors.
Brown material includes dry leaves and grass; paper and wood products, including shredded newspaper and torn cardboard; dryer lint; old pet food; straw, and the woody stalk of plants like corn and sunflowers.
Green material gives living soil micronutrients nitrogen, which is the protein they need to grow. Green materials are soft and sometimes wet: coffee grinds with filters, tea bags, fresh green leaves and grass clippings; fresh weeds before they go to seed; kitchen scraps, including washed out egg shells and fruit rinds; composted manure including rabbit, chicken, sheep and cow, and scattered hair mixed in well - don't throw it in all together or it may clump.
Although it's tempting to save your green material in the refrigerator until you can take it outside, make sure to clearly mark the container.
One summer when my brother David drove from the East coast for a visit, I found him happily munching on what he thought was a pre-made salad. I didn't have the heart to tell him he was consuming the leftovers from my cleaning out the refrigerator, originally destined for the composter: Romaine lettuce remnants, a couple of sad cherry tomatoes and almost-dried up blueberries he topped off with a light raspberry walnut vinaigrette.
Actually it looked pretty good.
Now that you have your materials in the composter, the best thing you can do is regularly turn it to get oxygen into it. The goal is to get materials mixed well enough that they will literally heat up and speed up the decomposing process.
If there is an ammonia odor, you have too much nitrogen or green material. Add sawdust, wood chips or straw.
If it's still cold, either you need more material or you need to add moisture. After adding water, mix well.
If the materials are moist, sweet smelling with some decomposition but still aren't "heating" up, add a nitrogen source, such as fresh grass clippings or manure.
With a little practice, you will soon easily be making compost and growing bigger, healthier plants. Did I mention at no additional expense?