Hi Ed,
when I first started and took my first clock apart I broke it, thought that was that and threw it away. It was only a cheap pin pallet time piece and had no value. The next clock I took apart and was a little more careful, I took my time, got it back together after fighting with the mainspring and it didn’t run. Neither did the next one, or the next……
What I am saying is dont worry about failure, failure is a word for a term -“I will come back to it later”.
Whatever we work on we learn as we go, if a clock or watch doesn’t work when we have serviced it I can bet we have still learnt something from doing it.
Take your time, walk away from it when it gets too much and ask as many questions as you like. We all get days with “failures”, dont ever think you are alone! 
Paul.
p.s. I still have some “failures” in my workshop, in boxes, waiting for when I have the right tools/experience to make them into successes
