I've done both, now have ground tank on a "skid."
For elevated, I made a stand and used 55 gallon barrels. The barrels would be removed when empty, brought to the pump and filled directly, then used the skid loader to put them back on the stand horizontally. I found some pressure relief vents for the 2" opening that had a manual vent as well, and the just standard 3/4" fuel filter housing, hose, gravity nozzle. It worked OK.
Problem is I had a leak with my kero tank on the valve, had to get the tank on the ground and upright. So there is that.
Now I use a 300 gallon gravity tank I picked up some years ago at auction for $20, converted it for ground use, and I use that. I have the Co-Op come out and fill it up in bulk. I put a Fil-Rite 120v pump on it and it has been GTG over since.
I intend on making a "fuel island" which will house this tank, my propane tank, and kero tanks, and put a roof over them to keep the sun off.
Keep in mind:
Gasoline needs to be stored air tight, but the vessel needs a pressure relief for safety. The pressure relief I put on my 300 gallon tank is 2 PSI IIRC. You also need vacuum relief, usually built into the same cap.
If you can keep the sun off, pressure is GREATLY reduced in the summer.
You now made your fuel storage very easy to steal, so guard it appropriately. I figure the best way for me to keep people out of my gasoline is to control the power to the pump. One of these days, I'm going to make up a little Arduino project that uses a PIN password to activate a relay that turns the pump on for say 5 minutes. I don't have to remember keys, can keep it plugged in, etc.
DO NOT FORGET GROUNDING!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!