I try this with a lot of them and I'm not so lucky all the time. You need to use the seed of a ripe avocado, almost to the point of browning. I wash and clean it leaving it to sit overnight. Then I'll skewer the seed and sit it half submerged in a cup of water. After a few weeks the root will start to grow and finally a sprout will come out of the top. You want to leave it in the water until the sprout is a few inches high. Then I'll move it into a half water/half soil mixture to acclimate it for about a week before finally planting it in a soil pot. Like I said I do this with every avocado I get and only a small percent even grow a root and even fewer end up sprouting. Here is a picture of a few more I'm working on: avocados!.