If your soil presents specific problems with its structure—for example, being very wet or very dry—rather than expend great quantities of energy trying to bring it closer to the norm, you can always copy nature, and grow those plants that will thrive naturally in such conditions.
For instance, if you have an area of land in your garden that has poor drainage, often caused by heavy clay soil, you have the ideal conditions in which to create a bog garden. The virtues of a bog garden are that the plants that thrive there are usually large and lush with beautiful foliage. So, before you drain the site, think about whether it might be worthwhile adapting to the conditions that you have, rather than the reverse, and growing what nature intended for it.
If you have very sandy soil, you may want to grow those plants that will do well in those conditions. Cactus and succulents will be very happy in sandy soils that contain little to no nutrients and hold little moisture.
When you are buying a plant from your local nursery, tell your nursery professional about the soil types you have and ask them to recommend those plants that will thrive in your specific soils. It is better to work with nature, than to try changing it. Sunlight and moisture should be considered prior to buying any plants. Keep in mind that all plants will do better with organic materials added to them, regardless of their indigenous setting.