what is the ground you are going into? or is it over a concrete slab?
the first thing that springs to mind is using concrete strip-footings as bearers.
the second thing that springs to mind is your joists will need to be wet-rot resistant.
the third thing that springs to mind is you'll have to sterilise the ground or use extensive weedmatting over a bed of compacted sand to ensure it doesn't turn into a nice raised-level patch of grass
r's brynk