What can I compost?
If it can rot it will compost, but some items are best avoided. Some things, like grass mowings and soft young weeds, rot quickly. They work as 'activators' or 'hotter rotters', getting the composting started, but on their own will decay to a smelly mess.

Older and tougher plant material is slower to rot but gives body to the finished compost - and usually makes up the bulk of a compost heap. Woody items decay very slowly; they are best chopped or shredded first, where appropriate. For best results, use a mixture of types of ingredient. The right balance is something you learn by experience.

Hotter rotters (activators): Comfrey leaves, young weeds, grass cuttings, chicken manure, pigeon manure.

Medium rotters: Fruit and vegetable scraps, tea bags, coffee grounds, old flowers, bedding plants, old straw and hay, vegetable plant remains, strawy manures, young hedge clippings, soft prunings, perennial weeds, gerbil, hamster and rabbit bedding, wood ash, cardboard, paper towels and bags, cardboard tubes, egg boxes.

Slow cookers (very slow to rot): Autumn leaves, tough hedge clippings, woody prunings, sawdust, wood shavings.

Do not compost: Coal and coke ash, cat/dog litter, disposable nappies, glossy magazines, meat, fish and cooked food.

How to make compost:
You can make compost simply by adding compostable items to a compost heap when you feel like it. It will all rot eventually but may take a long time, be a bit smelly, and might not produce a very pleasant end product. But with a little extra attention - taking the Cool Heap route outlined here, you could improve things dramatically. If you want to produce a large quantity of compost in a short time, and are able to put more effort into it, follow the Hot Heap route.