Once you know where you want to plant, it's time to check the soil. Soil testing is the least glamorous part of gardening, but the most important. At the very least check your soil's pH
. This will tell you how acid
your soil is. Plants cannot take up nutrients unless the soil's pH is within an acceptable range. Most plants like a somewhat neutral pH, 6.2 - 6.8, but some are more particular. If you are growing plants from the nursery, check the plant tag for specifics. If no pH preference is listed, a neutral range is fine.
You may also want to check the texture of your soil or even the nutrients and minerals in it. You can have that done at your local Cooperative Extension office and some nurseries. Soil texture refers to whether it is sandy, heavy clay, rocky or the ideal, a sandy loam. Whatever the texture, it can be improved with the addition of organic matter such as compost.