For clay soils, add organic matter such as compost, manure or peat moss. Till or spade to help loosen the soil. Clay soils absorb water very slowly, so be careful not to over-water. For sandy soils, add organic matter to improve structure. Otherwise, water can move through the soil so quickly that plants won't be able to absorb it.
Loamy soil is the best kind of soil.
It's a combination of sand, silt, and clay that absorbs water well and stores it for plants to use. If you don't know your soil type, have it tested at the UVI-CES Soils Diagnostic Lab . Plant or mulch bare soils. Mulching reduces water loss and soil erosion. Replanting along with mulching will give you the best results.