Hey Herr_Reitz,
For me every match I begin with the thought "winning is all that matters" and this is how I play the game. I care about winning more than personal accolades and honestly if you are doing "your job" the damage and achievements will come. Granted there are some games that maybe losses from the early going, a DD dies early or a flank falls and this might change the way you play. If you go in with the mindset of trying to win every game and doing what you can to make this happen you will win more games and get better individual results. Yes, some matches end quickly and there is nothing you can do about that.
I always tell players that you will get damage/achievements if you are helping your team win. If a game is so far out of reach that you don't see a possible way of getting back into it, then it might change the circumstances for that one match. In a team game you have to play for the team and that you will get good results from it.
Play to win the game, simple as that.
Damage and achievements will come as you play to win. Yes, it is hard to pass up that broadside cruiser sometimes but killing that DD will help win the game. This is one of those decisions you will run into a lot during the course of a match.
The ship you are using is also a valid reason to do things differently. I wouldn't play the Des Moines the same way I play the Henri but they both serve their purposes.
Communicate to your teammates with last known spots or other relevant information but don't spam the map =).
Hopefully this answers a little bit of what you are asking and gives insight into how I play the game.