Tactics: Crackpot Tactics
Because sometimes crazy works.
In a PvP team game like World of Tanks, sometimes the predictable is exactly what the opponent will be ready for. In cases like those, doing the opposite of the expectations can catch an enemy wrong-footed and the team will be too slow to either react or exploit the weaknesses that crackpot approaches offer them.
Disclaimer: Using a crackpot idea doesn't guarantee good results, they are extremely situational.
These are high risk tactics with no basis in reality.
Risk everything, go all in! When the round starts, the enemy team will begin to disperse, but not you...you're throwing everything you've got at them from one direction. With good timing and luck, you can break through their base defenders and begin to capture the base before they're able to organize a counterattack or capture your own base. This is most often referred to as "rushing" the enemy. While very risky, the payoff can be very big. Generally speaking, however, this tactic often bogs down, allowing the enemy to penetrate through the opposite flank, and either capture the base, or flank your over-committed force.
Use expendable tanks to shield you. With the plethora of low tier tanks in training matches, they can be used as perfect height cover to block incoming fire against your hull. You can now move the wrecks very slowly to use as a mobile shield, thus a heavy tank can use a light tank to block off incoming shots. This is also a good tactic to be used with TD-ing artillery against a tank; if the artillery is small or at a high enough elevation over the enemy tank, it can use its artillery mode to hit the enemy tank without risk of counter fire. Use movable wrecks to your advantage!