Once you get Bow Expertise up a couple levels (for a faster attack) and your agility up enough to use better bows and raise your offense / defense, things will be much easier and require much less run in the hit-and-run tactic.
True Shot is broke, but Splitting Arrows (mobs), Poisoned Arrows (all) or Explosive Arrows (area effect, I think) will make things easier.
As a survivor ranger on hard, I had to use a scorpion for the skeleton boss that shoots fireballs when opening 1 of the 4 tombs in the catacombs (made sure I got the last hit in for the experience points). If I stopped long enough to shoot at him, he would get a shot at me; I could kill him in a hundred(?) hits, he could kill me in two.
