For 90% of the problems I see, there are three main solutions:

• Plug in the loose cable / turn it on.
• Read the error message, and do the obvious thing.
• Get a mechie to fix a broken part.

Solution #2 there is the hardest to train, but is the most rewarding. I have often heard "... just teaching me to read again..." said with a smile. (Attitude and atmosphere are very important)