Measure the amount of space you have available for the shed. Measure the width, lengths and height of the space with a tape measure. This will determine the sizes of sheds from which you can pick. Take the measurements and tape measure with you to the garden shed retailer and measure the width, length and height of the sheds.
Measure the tools and equipment you desire to keep in the garden shed to find out how much space you'll need inside the shed to accommodate them. Measure the width of the largest items to know if you need a single- or double-door shed. Measure the length of your longest tool to know how tall your shed needs to be. If you want to have a workbench inside the shed, take that into account for space.
Map the layout of your shed on a piece of paper. Use the measurements of the space, the shed and the tools and equipment to organize the shed on the piece of paper. Use a pencil so you can erase as you go. Consider if you want to have windows in the shed and if you want it to be made of wood, fiberglass, plastic or metal. All of these factors determine the cost of the shed. Provide enough space inside the shed for moving around.
Pick a shed that fits in with the decor of your home and landscape. You don't want a shed that is going to stick out like a sore thumb. Consider the roof and shape of the structure and how it fits into the overall plan of your yard. If you want a shed to have plumbing and electrical, consider purchasing one that comes pre-wired and pre-plumbed.