Diagrams and Schematics

Some things I've learned at school have helped me in my life.  For example:  we had to wire up a switch for hazards, left turn signal and right turn signal.  Some guys and I stumbled around for about 45 minutes, trying to figure out how to wire the switch.  Our instructor then gave us the wiring diagram.  We proceeded with the wiring and it was done in no time.  If you don't succeed the first time, read the directions!  Another example:  A student brought in a car to have her door lock switch fixed.  I was test probing around locking doors, unlocking doors, not knowing what I was doing.  I then printed out the schematic and found the car runs off relays, switching grounds to make the doors lock and unlock.  So what I've learned is wiring, diagrams and schematics can be your friend.