Grass clippings are all greens and won't compost correctly.. Some clippings are fine, but you need an equal amount of carbon (browns) or the process doesn't work.
Greens are easy to find.. food, grass, etc. its the damn browns that are difficult. Sawdust is the best.. wood ash works good.. throw in some sticks and twigs to help break apart clumps. You need a 50/50 mix or it doesn't work and can start to stink.
Greens are waste products.. but you have to work to find the browns.. My table saw has a box below it that collects the saw dust.. I save that stuff when cutting clean lumber that isn't pressure treated.
News papers make great browns too.. just make sure its the dull paper type, not the shiny wax coated advertisements.
To much brown and nothing happens (not so bad), but too much green and it turns to mush and smells horrible.
A composter that is properly balanced, or even roughly close to being properly balanced, won't smell.. The problem is people think they can just throw in the food and it will break down into rich soil.. but the reality is that it will just stink like a garbage can.
If you find too much moisture, add cardboard or leave the top open so it evaporates on a hot day.. if you have too many browns, you can pee in a bucket and dump it in.. Urine is loaded with nitrogen.. or just dump in some grass clippings if you want to avoid the yuk factor.
Make sure to rotate once a week.. a good two or three turns to spread around oxygen. If you don't, it can go anaerobic and stink.
