What you should do is join an astronomical society/club and go to a few of their nights. See what the other members are using for piccies and learn from their experience. You're going to need some sort of guidscope/autoguider combo to guide your scope for taking piccies of DSO's, otherwise you'll be limited to subs 60sec or shorter.
Best also, to learn the night sky first. Otherwise you're going to get lost and rather frustrated trying to find targets. Grab yourself a copy of
Stellarium and also a good set of starcharts in book form.
As far as the method you're going to use to take the piccies, that's up to you and whatever the circumstances you find yourself in (as in what equipment you have, where you are etc etc).
As far as keeping busy goes, you're going to have more to do than you can imagine
There's plenty of targets out there for you to have a go at.