installing aftermarket gauges volts/oil psi/airfuel

on a LS motor, where do you hook up the oil pressure sender unit? obviously somewhere on the motor and apparently near the oil filter but i wanted to know exactly where? anyone who has hooked up a volt gauge, obviously black goes to ground but wanted to know where you guys put your positive wire(it says to a 12v source)? and for the air/fuel gauge, my O2 sensor has 4 wires and know that the white wire with a black line on it is the signal wire, how did you guys hook it up to it? move the wire cover and hook it up there? or where?
and on all gauges like i asked earlier, where did you hook up your +12V wire?
thanks for any help