As a DPS... a good healer REALLY makes or breaks an otherwise good group. Those clutch heals when the opposite team rushes one of your team members are extremely important. That said, I understand when people are learning and I'd rather give advice than just insult you for being new (that's silly). I don't play a healer but hopefully others have some good advice for you. The best healers I see are always on the move... always running, making it hard for people to catch up, dashing across the arena, and giving people heals as they go.

If you are new, make sure you at least have decent gear before entering pvp. I once entered a match with a dude in valentoine's gear and that really annoyed me because he was clearly not even going to try. There is currently no matchmaking, so it is possible that you will get pitted against rank 30 pvpers with i90 pvp gear... and even if you are the best player in the world, you probably won't outlast. Some veterans suggest starting off with level 30 or 40 matches, because everyone's gear scales and you are on an equal playing field with more experienced players when it comes to gear. If you want to do level 50, I suggest going at odd hours (not primetime) because then you are less likely to be matched up against i90 premades (3 people and a random).

A few notes here...

1) Morale does not count at all in level 30 or 40 pvp. Even if you have pvp gear, it's better to put on pve gear for these lower ranks because morale doesn't scale -- it's just not there.
2) If you have i70-i90 pve gear, it is better to wear that than the i55 pvp stuff. The general rule of thumb is... if you have i70 pvp gear, replace your pve with it... otherwise, keep using pve until you get the pvp gear to replace it. (The extra stats such as base MND counteract the effects the morale would give you from i55.)
3) Don't forget about the abilities you can buy! Each rank up in pvp gives you one point, and three points will buy a new ability. Choose wisely.