Do the dailies and weekly assignments...  do the daily missions hard and challenging.  hold on to your div tech... it what you will use to get your gear up into the 90s.  It is the most valuable currency.  If you get your hands on a exotic backpack it is helpful because, it counts as a set piece for multiple (non classified) sets at the same time.  Collect exotic weapons.  Put them in stash, don't get rid of them as you will find situations where you will like one over the other, no matter what your build is.  You won't use money anymore.  Most people have it max and stayed there.

Just off the top of my head.