I don't put weedy stuff in the bin, or cooked food or meat scraps. Woody prunings take a long time, but you can help by cutting them small or shredding them. I put in general kitchen waste -veg peelings, tea bags, egg shells, coffee grounds etc. The vacuum cleaner gets emptied in there too, and torn up egg boxes and thinnish cardboard. When I'm gardening, I tend to have 2 trugs, one for weedy or diseased stuff which goes in the council bin, and one for the rest of it. I've got 3 bins, one being filled, one rotting down and the third ready to go. Mixing the contents does help, if you google 'compost aerators' you'll find a bunch of nifty tools for use in a dalek type bin. Keeping the contents moist helps too as well, and I occasionally sling in a handful of pelleted chicken manure to act as accelerator. I don't have any lawns, so don't have any grass trimmings to deal with, if you do, then I understand they should be added in thinnish layers. Drainage can be inhibited if the composter is on hard standing (like concrete or paving).