In landscaping, aesthetic considerations exist--choosing an overall style, adding interest with flowers and trees, and working with texture and color to create pleasing patterns. These need to be balanced against practical considerations such as designing easy to use paths and minimizing the amount of water needed to maintain your garden. Combining the two is part of the art of landscape design.
The best plans are useless if they are frustratingly impractical, so first list the needs you need to meet. These may include: creating a children's play space, low water use, hiding garbage cans, producing flowers for cutting, capturing runoff in a rain garden, screening a neighbor's windows and hiding an unsightly propane tank.
Choose an Appropriate Style
You may love Japanese serenity in a garden, but that would look out of place next to a Victorian mansion. List your likes and dislikes, find photos of gardens that you love, create a scrapbook of possibilities, then decide which ones would look well around your home. Your garden is, in many ways, an extension of the house, an extra room. Create it to enhance the architecture rather than detract.
Draw Lines and Shapes
The shapes of paths, lawn and garden beds are yours to play with. Use a garden hose to lay out curves or, for straight lines, use stakes and twine. Large simple geometric shapes such as half circles, rectangles and broad curves are more pleasing than fussy in-and-out wiggles. Lawns, in particular, need to be pools of cooling green rather than vague shapes.
Add Height with Trees
Few elements of a garden are loved as much as a beautiful tree. Spend the time to choose well, considering the ultimate height (don't plant one that will get too tall and need to be taken out,) fall color, flowers, branching pattern and whether or not the roots are spreading and greedy for water, possibly invading the septic line. If you have space for only one tree, try to get three season interest, perhaps with interesting winter bark, flowers and fall color.
Stand at your windows and plan where to put beds of perennials, flowering shrubs and bulbs so that they will be seen to best advantage from inside the house. Or stand at the entry to the house and plan your view from there. Always put most of your energy into the areas that will give you the most satisfaction, perhaps at the entry or beside your driveway, where you will see flowers most frequently.