Hi
First you'll want to check with building codes lol. My prefab was damaged by Frances and Wilma finished it off lol
I mistakenly tore it down and was going to rebuild a multipurpose structue but discovered that the old was too close to the property line. Could have repaired the old but can't build a new structure. I don't want it anywhere else so have done nothing as yet.
Some design ideas that come to mind are be sure it's tall enough to stand up in. Good venilation .During summer I could use the old one as a smoker lol. And last but not least STRONG there'll definitely be some more hurricanes gary

Awhile back I bought a book at Lowe's on backyard garden sheds and structures. It provided information on everything from a simple 6x8 on skids to a large structure with living quarters upstairs! If you can look around and see if can find similiar books. (I wish I could give you the title, but it is lost somewhere in my mess.)

The advice about checking with your local building permit and codes enforcement office is very good. Sometimes you not only have set backs to worry with, you also have to worry with utility easements. (My brother has a power line that runs across the back of his yard, so the back thirty feet of his lot has to remain structure, tree and bush free.) Another reason for doing this is you might find that you are exempt on building "portable" sheds; ie a shed on skids, not attached to any permeanant foundation.

Whatever design you like and can afford will be limited by the limitations of the size of your lot, but on site storage is much nicer than having to rent a storage unit and then never having anything at home when you want it.

Kevin