STRENGTH IN NUMBERS: Have you ever seen someone do this (or have done this yourself)? A long line of tanks streams into the opponents base or tank hoard one at a time. BAD IDEA.Doing this is like sending the tanks individually to fight against a group of your enemies tanks. What you should do instead is to get them together in one large group outside of their base or tanks hoard and then send them in. If you are still having troubles keeping them together, give them a team number (which you should always do any way) and then press F to put them in formation.

TARGETTING: When in a tank battle, tell all your tanks to fire at one target at a time. This way you quickly eliminate tanks that would otherwise continue to fire back during a slower death. This seems to be an extremely obvious thing, but it is still surprising how many people don't understand it (especially newbies).

DANCE LIKE A BUTTERFLY, STING LIKE A BEE: When in a large tank to tank battle don't just sit there telling your tanks which target to hit next. You are leaving them as easy targets for the enemy tanks. Instead, fire off a round at an enemy tank then have your tanks move while they aree reloading then fire, move, fire, move, fire, move, etc. There are several ways you can do this, but most people find it easiest to just hit the X key to tell the tanks to scatter. However you do it, keeping you tanks moving reduces the damage they take.

DIVIDE AND CONQUER: This may at first glance appear to conflict with the idea of Strength in Numbers, but you should realize that it doesn't have to. When you get a large enough group of tanks, it is useless sending them all to go fight. What will happen is that the tanks on the front lines will be doing all the fighting, and the rest will be milling around getting in the way. Instead, assign your tanks to 2 or more teams and send them at your opponent from different directions. Not only will you make the most of you tank force, but if the enemy was not prepared to defend from several directions (ie the only have 1 team of tanks) they are going to suffer severely. The downside to this of course is that you have to pay close attention to both teams at the same time. This can get tricky, but with some practice it yields great results.