Before choosing any plants, know the cultural conditions of your site. Draw a map of the property and mark out the areas that are in full sun, shade and partial shade. Also check the soil in different areas of the property for moisture content. Know where you will be placing trees since they will change light and moisture levels. Know the USDA hardiness zone of your region so you can select hardy plants.
Now that you know the limitations of your site, it is easier to choose the right plants. If you have a list of desired plants research their needs. Choose a nursery and do a trial run. Bring your plant list and jot down any new plants you see and want. Now take your list back home and complete your research. The healthiest plants are those grown in optimal conditions. Know the mature size of the plant in order to give it ample space. Most lists will change a lot after going through this process. Money saved on plants can be quickly lost if unsuitable plants die. If this part seems overwhelming plan and install one area at a time.
Before bringing home plants you will want to improve your soil. Soil is amended for structure, PH and nutritional value. Since tree roots go deep, they will need to adapt to native soils. A common practice is to plant all the trees the first fall so they can become established. Tree roots continue to grow during the winter. Perennials can be installed in early spring or in the fall. All of the soil can be amended for perennials if needed. Unless the soil has been significantly altered the PH should be in line with native soil conditions. If you want plants with very strict PH requirements do a PH test. If soils are laced with sand and rock or hard clay, amend with topsoil or a landscape planting mix. Soil amendments can be purchased by the bag or by the truckload.
Do not assume all the plants at the nursery are hardy for your region. The size of the plants you buy will depend on your budget. Sometimes a 5-gallon shrub is only a few more dollars than a 1-gallon size. Be more generous when buying trees and shrubs. Perennials fill in quickly so purchase them smaller. look closely at the foliage for any sign of insects or diseases. Make sure the plants have not outgrown their containers and become root bound. Before planting loosen or cut any roots that are growing in a spiral. Let your plants acclimate a couple of days in the containers before planting. Install plants in the morning or evening on a cool day.
The soil is ready and the plants are purchased. You chose carefully and did your research so now be creative. Do a preview by arranging the containers in your garden. It is still possible to make some changes. The rule of thumb is to install plants at the same soil level as they were in the container. Fill the hole with water, drop in the plant, replace the soil and water again. Place a 2-inch layer of compost or mulch over the soil to hold in moisture.