need to mix the greens and browns. You've probably got too many greens in there so you'll be getting a wet smelly sludge.
Stop putting fruit and grass cuttings in for a bit, add dead/brown twigs and scrunched up cardboard (the 'raw' kind that degrades reasonably, e.g. egg boxes), tea/coffee and eggshells so it looks a bit more fiberous and after turning it over with a fork it keeps plenty air inside.
Make sure the composter has plenty ventilation, doesn't get sodden in rain (+ good drainage) and getting a little sun - preferably with an open bottom directly on soil so worms can get in.