very hard to keep team mate a life or i become big target

 

Don't become a target since if you die then the person your healing will die to. Best thing to do is to heal them from behind cover if possible and if not heal them and try and dodge attacks. Always heal people that are out of battles it could save there life from a sniper. Try to attack the enemy while healing or even weaken there armour.

 

I think figuring out the best parts on each map that provide cover for the scientist, and having your team circling around those spots to defend you. Your the best healer I've seen, but developing a strategy for your team mates that is map specific is key.

 

Bro, I just looked at your sig, and realized you're on my friend list!

 

Heal the Titans mostly. Heal everyone else only if they get close enough.