Imagine what your patio area will most often be used for. You may plan to entertain lots of outdoor dinner guests. If so, be sure your patio space has plenty of room for the largest number of people right from the beginning. Your patio may be more of a private, reflective retreat for enjoying the sun, reading a book, or gazing up at the stars. Determine the use of shade, open sun, or even covering it with a roof. Now take your favorite ideas and put them into your rough plans - and soon you'll have a design that is ready for action.
The next step is to create your garden and patio design to scale - you can use landscaping software for this, or do it by hand. Choose the flowers you intend to plant, noting how many you will need for each month of your growing season, and select the landscaping structures that will give your design its form.
Some say the secret to a beautiful garden and patio design is having a good amount of hard structure. This is what landscape designers refer to as "good bones" - walls, fences, garden bridges, gates, garden arbors, landscape statues, garden fountains ... even a strong line of evergreen plants.