This is a very important component to the landscaping field because single family homes built within the last twenty years typically have very small yards. Backyard space is limited to essentailly a patio. Other homeowners have swimming pools, which take up most of the backyard. So you are left with a small courtyard, patio, or deck for landscaping. Here are some ideas for those with patios, small yards, courtyards, and decks.
You'll become very adept at selecting pots for growing plants. Use shelving. Plastic slelves are available from big box retailers such as Walmart for very cheap. Place the shelves towards the south or southwest in the northern hemisphere to allow the plants on the lower shelves to get light. If the patio is covered, use shade loving plants in areas that don't get much sun. You can use a watering can or drip line for irrigation. Complete drip kits that connect to your garden hose are redily available. If your patio is carpeted, and you don't want to get the floor wet, use flat pans outside of the patio to soak the pots as needed. Your ideas here.