I did it some years ago - I assume this is a wooden shed? The main thing was just to take out the windows first, then get out the sledgehammer. Yes, don't knock the walls out and be surprised when the roof lands on you. Obviously there are going to be nails sticking out and so on. It helps that the shed is usually falling down anyway, or why replace it? I had help, probably better when there are bigger bits to handle (and to catch any falling roof sections).
