Delivery pressure depends on the gun. Usually around 28-30psi.
Always use the switch on the compressor, don't switch on/off at the wall. The pressure switch will unload the pressure in the head allowing it to start easier. Best to plug straight into a wall socket. Use a longer air hose if you need to work away from the compressor, reduces voltage drop. Empty your tank regularly. They fill up with water.
Some compressors have a constant run option rather than start/stop. These will reduce load on your system.
As the guys said, get a gravity fed gun, find out how much air you need and then get a compressor with enough capacity and allow extra so it isn't running flat-out or you will kill it.