Avoid composting diseased plants, weeds and seeds, or invasive weeds like morning glory and nutsedge. Kitchen peelings and coffee grounds can also be composted, but avoid adding table scraps because they may attract animals. Not if they have good ventilation. Odor-causing bacteria are killed by heat within the pile. If animal manures are added to the pile, some initial odor can be expected, but it will soon stop as the pile matures.
Large piles break down faster than smaller piles, but they are also more difficult to manage.
Decomposition works best if some type of simple structure is used. Any type of structure can be used, including welded wire, fencing, pallets, or blocks. Leave open spaces in the sides to allow good air circulation through the pile and the bottom open to the ground. For best decomposition, it's best to mix a variety of materials. Most often piles are layered with whatever organic material is available at a given time.