For aiming tows in the Lav, ask Hydro, Chilli, Riker, Seabee, Raiden, viper_strike. In terms of being a great team player try and emulate Hydro's play style.
On a broader not on the AH in particular, as this seems to be your interest -
Remember being a good AH pilot or LAV player goes far beyond how good your accuracy is with any given weapon. Its about target selection, planning, situational awareness, manoeuvring and how you're assisting your team. You should probably work on these other aspects first before you try and refine your accuracy with weapons.
In AH my focus is always prioritising armor targets that are on or close to caps as it allows my teams to gain ground more easily, I don't go out of my way to target air targets unless I see a good opportunity for it. I usually ignore AA if in good cover because I can still wipe out a piece of armor on an attack run ( even with no gunner ) before I need to break off, If AA is exposed or in a problematic position I will put a higher priority on it,