Most fruit trees are not self-fertile, meaning that you need to plant two or more varieties in order to get fruit production.

Apples are generally not self-fertile.  Use two or more varieties to insure best production.  Choose varieties that bloom at approximately the same time to make cross-pollination possible.  Bloom periods normally last 5-7 days.
Apricots are not self-fertile.  Two varieties are required for fruit production.
Cherries are sometimes self-fertile, but  two varieties ensure fruit production.
Pears are generally sterile.  Best production will result from at least two varieties.
Peaches are self-fertile.  They do not require a second variety for pollination.
Plums are generally sterile.  Use Toka or American Plum as a pollinator.

Planting

Fruit trees are generally quite tolerant to a wide variety of soil conditions.  They do not like to be continually wet though, so low spots in your yard should be avoided.  Heavy clay soils should be amended to provide better drainage.  Plant in full sun locations for best fruit production.  

1. Dig a large hole at least one foot wider all around the plant than the container or ball size, and to the proper depth.
2. Be sure that the graft union is above the soil surface.
3. Fill in soil around the roots, and gently tamp in as you work your way up to fill in any air pockets.
4. Water thoroughly.
5. Mulch.

General Care

There are a variety of pests & diseases that can be a problem for fruit trees, but there are some simple steps that you can take to ensure a bountiful harvest.  After planting the right tree in the right place, the next step is proper fertilization.  A soil test should be done to determine what nutrients need to be added to your soil.  If a fertilizer test is not done, a general fertilizer such as 10-10-10 can applied at the following rates for each tree:  1 lb. the 1st year, 2 lbs. the 2nd year, and 3 lbs the third year.  Do not fertilize more than 4-5 lbs. per year.  The fertilizer should be scattered around the base of the tree out to and a little past the drip line of the tree canopy.

In order to control disease and insect problems, good sanitation is a must.  Always prune out any dead or diseased branches, remove dried or shrunken fruits, and dispose of any leaves and debris from around the trees.  Pruning tools can be disinfected with a 10% solution of bleach before and after use to prevent diseases from spreading with the cuts that you make..

A general purpose fruit tree (fungicide & insecticide) spray should be used starting with the 1st signs of emerging leaves in the spring.  Trees should also be sprayed when blooming starts and every 10-14 days for another 2-3 applications.

Pruning

Pruning and training your fruit trees is important to create a structure that will yield the maximum crop of fruit.  A properly pruned tree also encourages an open canopy for good air circulation that helps to prevent disease problems.

There are basically two types of pruning when it comes to fruit trees (or any plant for that matter).

1. Heading Back Cuts.  Cutting back part of a shoot or limb.  Tipping leaders for example.
2. Thinning Out Cuts.  Removing an entire shoot or limb.  Removing water sprouts, dead, or diseased branches for example.