Selection of the Tree-
Research your climate zone and note the number of chill hours in your area. Chill hours are the amount of time average temperatures remain under 45 degrees Fahrenheit. The chill hour requirement is different for all types of trees and meeting the required hour will mean getting fruit or not on your tree. Pick trees that meet your zone requirements and ask your nursery staff if they require other pollinators, or if the tree is self-fertile.
Planting Instructions-
Dig a hole. Hole should be twice as wide as the diameter of the root ball and just as deep as the root ball. If roots are tightly bound, loosen them so they spread easily. Place tree in hole so the base of the trunk is level with the ground, do not plant the tree too deeply. Firmly tap soil around root system while adding water to eliminate air pockets in the root zone. If gophers or moles are prevalent, wire baskets should be used in the root zone to protect from harmful (as often fatal) damage.
Amending the soil is not necessary provided that it drains well, isn't too clay based, and contains organic matter. If the soil is clay-like, either plant some where else, or add gypsum and compost to the existing soil and mix before planting. Fertilizing your trees isn't necessary during the winter months. Fertilizing should be limited to when the tree is carrying leaves or when in blossom.
Prune your trees yearly to promote growth, fruiting, and overall appearance. There are many great tree maintenance books available, such as; The Illustrated Guide to Pruning by Edward Gilman. Another useful resource is Peaceful Valley Farm Supply's website which features helpful videos on the subject as well.