Draw a map of your property as it is, and use it to decide where the new garden features, beds, and plantings will go. This will keep you from making mistakes when you start buying and planting. The map needs to be to scale -- an exact replica of your property in miniature. Many designers use a scale in which 1/4 inch on the plan (a single square of graph paper) equals one foot in your landscape. This scale usually provides enough room to show considerable detail but is likely to require the use of oversized paper to fit everything on one sheet. You can tape several sheets of graph paper together to get the size you need.
This is a good opportunity to decide what to keep and what to eliminate from your current layout. What do you like about your home's existing landscape? Perhaps its pavements and patios are already the way you like them, and you just want to expand or beautify the gardens. Perhaps there are treasured old trees that have taken generations to grow. Perhaps the existing shrubs are good but overgrown and need professional pruning, not total replacement. Perhaps your grandmother's iris is overgrowing its space. It can be divided and used as a mass planting elsewhere on the property. Look over everything with a cold eye and evaluate whether it looks good, is in good shape, fits your plan, and should be retained somewhere.
You have four options with every feature: keep it, improve it, move it, or get rid of it. It takes many years for a tree to mature, so think twice before cutting one down. If it's gone, what will the view be like? Its replacement may take too many years to grow to fill the space, so consider whether shaping, thinning, and pruning an existing tree will make it a grand part of your plan. Nonetheless, if a tree is badly diseased or damaged, it may not be salvageable.
Once you have your measurements and know what you want to keep and what you would like to change, you can get started on your scale drawing. Even if you're not much of an artist, the tips on the next page will help you make a neat drawing.