Level the ground of the site where the shed will be built. Leveling the ground as much as possible helps eliminate the need for excessive blocking, and makes the building process go much more smoothly. Prepping the ground will also prevent settling from occurring.
Clear out the area where the shed will be going of any obstructions, including weeds, shrubs, branches, and tree stumps. A great option is to lay down a sheet of garden fabric, or weed-proof membrane to effectively block weeds from growing once the shed is built.
Consider pouring a concrete pad, or laying gravel in the area for an extra sturdy base. With a concrete pad, you have the option of getting a shed with no floor, and attaching it directly to the concrete pad. If you prefer gravel, then you have the benefit of the extra support that gravel can provide.
Make sure there is plenty of room around the perimeter (2’ minimum) of the shed for building and ease of access. A common mistake is putting the shed too close to the property line.
Be sure to factor in height restrictions. If the shed is going to be placed up next to a house, it is important to have at least 1 foot in-between the roof of the shed, and any eave that it will be going underneath.