The first thing one needs to do is keep your plant watered. Water your potted plant when the soil becomes dry. Do this until you can get it into the ground. If you are experiencing extreme heat, take measures to keep your plant at least partially shaded, protecting it from the harshest conditions.Dig a large hole. For smaller/younger plants, your hole needs to be several feet accross, and also several feet deep. For larger plants, as well as small, the general rule is that the hole's diameter (from one side of the hole to the other) should be two times the width of the root system when it is spread apart. Place some dirt back into the bottom of your hole. Place your tree upright into the hole and begin to backfill the hole with dirt, and if desired some premium soil from your local garden shop. You want to be sure that the original soil line of the plant is even with the ground. While filling, pack the ground gently and add water to fill any air holes.Most new trees/shrubs need general watering the first weeks/months they are in your yard. During a dry spell, be sure to deeply water your tree and the surrounding soil once a week. Mulch is a garden's best friend. It is a true workhorse for your garden. It holds down grasses and weeds that will compete with your new plants roots for water, and also helps the soil retain water. It helps the soil from becoming overly compacted and acts as an insulator during the winter months. Create a mulch bed around your tree that is 2-3 inches thick, while encircling your tree with a several foot diameter of mulch.