Always Reload Ammunition
Make sure before you go into battle your tank has as much ammunition as possible. It's also a good idea to stock up on health kits and fire extinguishers.
Stay Together
Always keep close to your teammates as this will increase your chances of survival if you encounter a group of enemy tanks. You have no chance if you are caught alone by multiple opponents.
Flank the Enemy
Instead of approaching the enemy head on you may want to consider trying to attack your opponents from the side or behind where the armour on tanks tends to be weaker. Having the element of surprise will also enable you to do more damage.
Ambushes
Be weary of hills that have rocks and trees on them as these are potential tank destroyer hideouts.
Check the Radar
During a battle it is important to constantly check your rader for enemy tanks and for planning where you need to go while completing objectives. The radar is located in the top left corner of the screen, your tank is a white triangle, your teammates are green and the opposing enemy is red. The objective will be shown with a dotted circle around it.
Upgrade
Make sure you spend the experience you earn to upgrade your tanks. During battles make a note on what needs improving on your tank and then at the end of the battle upgrade accordingly.
Tank Crew
Don't forget to also spend the experience you earn to master your tank crews. Having a tank crew that is proficient in Firing Accuracy, Loading Speed, Aiming Speed, Mobility, and Range will help give you an advantage in battle.
Sniper Scope
Don't neglect to use you sniper scope as you maneuver around the map to take out your opponents from far away.
Tank Icons
Make sure during battle you keep an eye on the icons at the bottom of the screen as these show the amount of damage your tank has sustained. If you have taken a lot of damage you may need to consider retreating from the battle and calling your teammates for support.
Coordinate with Teammates
The key to success in this game is to communicate with your teammates using the chat commands to make sure you all have the same game plan for dealing with the objective.