The most important word for planning a project is just that — planning. When designing a landscape, it is generally best to start with the basics. What is the exposure? Are any hardscapes (paved areas like streets and sidewalks) involved or when will they be constructed? What kind of plants do you want? Are they compatible with the site? Are the plants suggested hardy in your zone? What kind of soil do you have? Does the soil need to be amended? What does your soil need? These are a few of the many questions to ask yourself before digging.
A well-tended garden will reward you with many years of pleasure.