For Sloped Sites, Build on Posts
If your shed site slopes, pouring concrete is a bigger job because you have to build strong forms and pour extra concrete on the downhill side. A simpler method is to build your shed floor like a deck, with footings, posts and a wood frame covered by plywood. If you don't like the opening under the shed, build a skirt to cover the space between the shed floor and the ground.
Since locating buried utilities is free, it doesn't make any sense to skip this step. You can avoid an expensive mistake, or worse yet, a tragedy, by going online to call811.com for more information and then calling 811 a few days before you plan to dig to have your buried utilities located.