The main factor to be considered while you plan what to grow in your garden is choosing an appropriate area where you can work with the gardening tools. There are lots of points to be kept in mind like the area chosen, how you plan to water them, the required amount of shade it needs and so on. So a good thinking is to be done as whether with all the efforts taken if the plant and the garden is going to survive or not.
The most important is planning your garden in your piece of land that will supply the most required climate for the plants grown. As I am not aware of the type of garden you are planning to start I am unable to give you any proper tips on it. A search in the Google will provide you with a number of sites which gives data on the exact conditions required for growing each plant and once you are aware of this it is your choice to select the shaded or the sunny point in your land.
Yet another most important aspect is the watering of the garden and if the sprinkler system is already set up for the grass, the middle of the land is the best place to start your garden as it get watered and requires not much of strain from you. In case there is not a good spot for your garden you have no choice other than watering the garden by a hose or pulling a sprinkler to it and the garden should be at a proper distance for the hose to reach it. So a proper planning well ahead is required.
It is a hard attempt to have an ideal amount of shade for the garden. One should keep a track of the selected spot of the garden watching and recording how much of sunlight and shade it gets each day. You can also refer to the website for confirmation and decide to choose a perfect spot for planting and creating a garden. But these keeps changing according to the seasonal changes and you should be able to make this out on a yearly basis. A shade can be put up artificially if required also to avoid excess of sunlight.
The plan of starting your garden is almost fulfilled when you have decided the exact area for the garden, the sufficient amount of sunlight it receives and the water requirements for it. There are other points also to be considered but you require a lot of common sense to select the area keeping in mind if you were the plant you could survive there? If you feel yes it is time for you to purchase the required soil and fertilizers to begin with. So have lots of fun gardening!