Keep in mind that the battery of a light general aviation aircraft is not made for being used for a long time on ground (except when the aircraft is capable to be powered by an external power system GPU or an alternate electric circuit).
Before the engine is running and the alternator is switched on, limit all use of avionics and lighting equipment.
Cessna 172 typical VFR+IFR cockpit that will be used for these beginner-level flight lessons
Depending on your platform and aircraft developer, instruments and equipment may vary.
Since there is no power supply active and the engine is not running, our instruments and electrical equipment is not powered.
This state is usually named "cold and dark".
The fuel tank selector is below the trim wheel and does not appear on this image. Since fuel tanks on this version of the Cessna 172 are equipped with a fuel crossfeed system, we must just make sure that the selector is set to "BOTH".
At this point, you should make sure that:
1. All switches are set to the "OFF" position
2. Avionics are not powered and indications are coherent
3. Throttle and mixture levers are completely pulled back
4. Trim is set in the "take-off" position marked by a white bar
The cockpit preparation is quite fast and simple for this typical single propeller general aviation aircraft since there is no data to be inserted into flight computers and no complex system to check