Determine the viability of your soils and sites for fruit.

To be truthful, you can grow fruit on almost any soil, but it may not be practical for every site.

Soils:  As a general rule of thumb, no fruit tree likes to have soggy "wet feet".  Soils should drain properly or should be modified to improve drainage, so that you don't have any standing water in the orchard for more than half a day or so after a major rain.  Different fruit types and rootstocks can be used to help "make up" for soils with drainage problems to a certain extent.  The "Rootstock Basics" page will give you a better understanding.  In general, avoid creek or river bottoms, because usually the soils are not well drained and are more prone to periodic flooding, which fruit trees don't like. 

Apples have the widest and most well understood selection of rootstocks that range from fully dwarf to semi-standard.  There are rootstocks that can tolerate heavy, wet soils and ones that need only well drained soils. Unless it is a swamp, then you probably can grow an apple tree there on some rootstock.

Pears have fewer rootstocks to choose from, but most rootstocks are quite tolerant of more poorly drained soils as well as lighter soils.

Cherries now have size controlling, "dwarf" and "semi-dwarf" rootstocks instead of just the old standard rootstocks growers had to use 20 years ago.  Cherries have more rootstock choices now, but in general still require better drained soils than apples and pears.

Other stones fruits like peaches, nectarines, apricots, plums, and prunes have few proven size-controlling rootstocks, and most of the standard rootstocks available prefer lighter, well drained soils.  "Wet feet" will often result in short tree life.

A good site is more desirable than the "best" soil  My father, Karl, always had a saying that your money was better invested in a good fruit site, rather than trying to improve a mediocre fruit site.  In general fruit sites are characterized by the following:    Higher relative elevation to lower ground, so that frosty and cold air has a place or empty reservoir to drain to; and a suitable soil type for the type of fruit you want to grow.  If you are in an area that hardly ever has spring frosts, you are really lucky!  However, most fruit areas have a predictable potential for damaging frosts at least early in the spring--- sometimes even very late frosts.  Wind machines, frost fans, heaters, irrigation and other frost fighting tools can always be used to help a marginal site produce fruit, but a "frost-free" site only costs you the price of the land!  

Always try to plant your fruit on the best "fruit site" on your farm.  Often this is land that is marginal for vegetables or cash crops, because it is hilly, rolling, and with "poorer" soils than what you would like for your other crops.  If you don't have the best site, then you will have to make up for it by modifying your growing practices and planting systems.