If your soil presents specific problems to do with its structure, (being wet or very dry, for example) 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 would thrive naturally in such conditions.
If you have a very sandy soil (or tend to forget to water) you may want to grow those plants that will do well in desert conditions. Cactus and succulents will be very happy in sandy soils that contain little to no nutrients and hold little moisture.
For instance, if you have an area of poorly draining land in your garden, often as the result of a 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 in these conditions are usually large and lush, with beautiful foliage. So before you drain the site, think about whether it might be worth while adapting to the conditions that you have, rather than the doing reverse, and growing what nature intended for it.
When you are buying a plant from us, tell us the soil type you have and ask us to recommend those plants that will thrive in them. It is better to work with nature rather then try to change it. Sunlight and moisture should be considered prior to buying any plants. Also keep in mind that almost all plants will do better with some organic materials added to the soil, regardless of what they tolerate.