Build the deck in the area you have allocated for it. When there is only a small space available, the deck can double up as a container garden, as there is likely to be limited space for flowerbeds.
Fill pots, containers, hanging baskets -- and anything else you choose -- with the plants you want in your garden. Herb pots with basil, cilantro, rosemary and chives not only look beautiful but are useful too. Large terracotta pots can be used to plant citrus trees and placed at the front of the deck as an "entrance." By combining beauty with bounty in this way, you will maximize the space available in a small backyard.
Plant hanging baskets with trailing plants like petunias and ivy, and hang them from walls or poles that are located by the decking area. This also optimizes the space by taking advantage of vertical gardening. Herb baskets can also be hung at eye level to maximize the space.
Grow vegetables in your garden that produce the most amount of crop in the least amount of space. Good crops to grow are beans, cucumbers, lettuces, spinach, kale and peppers. Vegetable plants can be just as beautiful as flowers, so give up the flowers in favor of vegetables in small backyards.
Grow a plant in every single corner and crevice of the backyard to make it appear larger. Even shady areas that receive little sunlight can be planted with hostas, ferns and brunnera.