Tactics.

[Mustang]

ATGMs are worthless if you know what you're doing. Usually, the enemy will have too many dug-in MGs for you to try a pure infantry assault, but mortars are good here. ATGMs, once they've been fired, are easy to spot, and it a turn or two you'll have a batallion of artillery supressing them to hell. If you can't do that, any kind of MG or rifle fire will do just fine, and if there's no other choice just put up smoke (few ATGM carriers have thermal).

As for my tactics, it depends on the battle. In an infantry engagement, I use a lot of MGs and snipers except in close terrain or on the defense. I also buy tons of mortars and use LOTS of smoke. Mortars are excellent because they're so cheap and almost as good for supression as field artillery. Even if you don't have any enemy infantry to shoot at, they're great for a quick smoke barrage. Smoking off part of the enemy force will allow you to engage the rest piecemeal.

But I agree with Kesh's idea of staying on the defensive in meeting engagments. Ideally, you should be able to rush for the center objectives and secure them, but if you can't, just dig in and launch a few pinprick attacks every once and a while to build up your score to compensate for the fact that you don't control the center objectives. If the enemy digs in too, your only choices are to attack or retreat, though.