First post (years of being a lurker and warhawk turns me into a member..finally)
Well I'm sure someone will put up a guide on GameFaqs soon enough. In the meantime the main thing I've learnt to use so far is using lock-on.
Hold down L1 when in a warhawk to lock-on missiles to an enemy (not just homing missiles), also hold down R1 when in a missile turret or when on foot using the rocket launcher for the same effect. The missile turret is particularly effective, I guess as it's firing two missiles it's just a bit more tricky for the warhawk to shake off.