When we had a smaller garden, I used compost bins I got from a local home center, maybe 3'x3' made of wire mesh. Start the compost and then move it to the other one, and start some new in the first one.
Now I just have a giant pile. Horse manure, grass clippings, weeds, household garbage, wood chips, dead rock squirrels (I'm still not kidding about this, I put one in there this afternoon), leaves - everything goes in there. I turn it once in a while, whenever I have the loader running.
If you have fruit flies, cover up whatever is attracting them with some dry compost, dirt, or whatever.
Composting is done by aerobic bacteria. If your compost pile smells, most likely anaerobic bacteria are at work and it needs to be turned. Grass clippings alone are quickly taken over by anaerobic bacteria, causing the smell. Mix in some "brown" stuff and it will work right. By brown, I mean wood chips, straw, dry horse manure, anything to let the air in.
What ilbob is talking about is called "sheet composting". It works fine, but uses more of the nitrates in the soil to make it work, which is fine also. I use both methods.
Spoiled alfalfa hay is one of the BEST composting materials, so keep your eye out for this, if you can get it cheap or free (alfalfa is extremely high in nitrates). Feathers work, as does hair. In fact, almost any organic material will work, including shredded newspaper.