Answer: I would start by analyzing the site: walk around it. Visualize plants of different shapes and sizes. Consider their needs for sun and shade. Sketch a plan of the bed you want to plant. Tall plants should go at the back of a bed that's adjacent to a wall or fence and in the middle of a bed that will be viewed from all sides. Plants that need frequent attention, such as pruning, grooming or spraying, should go where they can be reached without your crushing other plants. Spread 3 to 4 inches of compost and any other soil amendments over the top of the area and till or dig up the soil to a depth of at least 8 to 10 inches, up to 24 inches if you're planting perennials. Rake smooth with a ground rake, and you are ready to plant.
I can only suggest you choose the plants you love and set them in the garden then decide whether or not you want to add hardscape - paths, benches, arbors, etc. in the new garden area. There are lots of books on landscape designs in your garden center and in your local library if you need a little inspiration.
Best wishes with your new landscape!
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