I found that access to gear that helped me survive (armour, mainly, although some jewelry can be of great help) is the key, especially in mid-levels.
Invest your money and time in your bow. Have a good blade, but if the mob closes to melee range, you have half-lost. Keep them at a distance if possible. You excel at Range, but never will out-hack a real melee class.
Power. Put energy into maximizing and maintaining Power. Will for base Power, Fate for In Combat Power Regeneration, also direct adds to Power and ICPR. Mid-level (again, kind of a rough spot for Hunters) it gets very hard to keep enough Power to keep shooting in group situations and long fights. Practice those skills that reduce Power consumption or restore Power.
Read, lots. Inspect other Hunters you see, and don't be afraid to send a tell asking why they did something or traited something or equipped something if it doesn't make sense to you. Most Hunters, I've found, are more than happy to discuss it in Tells, and point out things you might have missed. (Sure, there are some that will be rude and tell you to do bad things, but those are likely Champions playing an Alt Hunter. ) (Just kidding, Lurking Champions!)
You've taken a good first step in asking here.
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