Make sure not to get ganked. Use Elune's Chosen very often, as the heals are stronger than you might expect. You can proc the healing from minions to keep a safe distance from enemies while healing your teammate. Use Starfall as area denial, help your team secure kills, or prevent the enemies from disengaging a fight. Make sure to practice hitting stuns with Lunar Flare, as they can help save a teammate or assist in winning teamfights.

Level 7
Kaldorei Resistance is a great alternative to Huntress' Fury if you don't need to worry about clearing lanes.

Level 10
Shadowstalk is a great heroic for healing teammates across the map or helping them escape tricky situations. It can also be used to engage, but probably better suited for disengage.