If quarters are tight, you may want to maximize every square inch. Think of your space from all angles, remembering to use hanging baskets, containers, and especially vines to help create the illusion of endless garden. Square foot gardening techniques are a definite option and will serve you well. The smaller the space, the more attention you need to pay to detail. This will help you hold interest within the space you control and away from neighboring distractions.
Optical illusions are also useful in a small space.
Often, space-enhancing tricks from interior decorating can be used equally well in the garden. You will probably be happier applying your efforts to a manageable space, perhaps 20 by 30 feet. Certainly no larger than that to start with. Fence this area off or otherwise enclose it from the surroundings to separate the cultivated from the wild. In a sense, you will mark out your garden room.