Planting an avocado seed is very easy: first, clean the seed; second, put about 3-4 toothpicks around the middle of the seed; and third, set it on top of a glass of water so the bottom half is underwater. Place it in a warm sunny window and change the water frequently; roots and a sprout commonly show up in a couple of weeks, and then you can put it in soil. For great success, a fresh seed is ideal, soil should not be too dry or wet, and the plant should be exposed to lots of sunlight.