Find a large barrel in the size you need for your composting. This can be a 22-gallon metal garbage can or a 55-gallon plastic drum from a local feed store. Whatever kind you get, be sure it has a tight-fitting lid. If it's a reused barrel, make sure it is well washed and free of any chemicals or residues.
The barrel must be aerated to let air circulate around the compost, drying it and helping it decay. You can make holes with either a hammer and nails or a hand or power drill. Use a heavy enough nail or drill bit to penetrate the barrel side and bottom.
Make plenty of small holes in the sides, anywhere from 100 to 200 holes. They should be just the size of the nail or drill bit; about a quarter-inch or half-inch at the most. Spread them out evenly so you don't weaken any one section of the barrel.
Add plenty of holes in the bottom for drainage of excess liquids off the compost. They can be a little bigger than the side holes, but they don't have to be. There should be between 12 and 20 drainage holes in the bottom, spaced out evenly.
Put the barrel up on bricks or treated wood blocks, to support the barrel's bottom. This will help with drainage and keep your compost barrel from sinking into mud.
If the soil underneath the barrel becomes wet and stinky, put down gravel between the bricks or blocks, so extra liquids drain into the soil and don't sit on the surface. This probably won't be needed if the barrel is in a sandy or loose-soiled area.