Try to understand how most things work and how, when they don't work, it affects your job..
Use your common sense: for example a capt's cup holder broken could wait until the night stop. Remember your aircraft is normally not the only one and for an engineer being responsible for a handful of aircraft at any one time, and sometimes all with defects, can be alot of pressure, so the worn capt's seat cushion can wait too as he/she might not appreciate it.
Talk to your engineers. A good relationship between flight deck and engineers is invaluable to any airline.
But most importantly, like any responsible job, know your limits and be able to but your hand up and say "I don' know".