With the latest version it's more important that someone dies by teamplaying than one player getting imba strong. I don't know what you already know and what not, so here a re some random tips.
- always use hotkeys [QWERT for spells, numpad for inventory items (there are tools to replace the numpad keys so you don't need to move your hand and save time, but i don't use them anymore)]
- take a random tank (hotkey: R) at start, you will get a bonus of 5% start gold, which is 150 gold for the most games [you can use it for a fast control point teleport or wait for about 30 seconds and buy a stronger weapon (like scout + electro cannon, heli + fireball for example)]; you should practice all 6 possible random tanks, if you can handle all you should try alternative builds to (i like to buy a tech-mech right at start, but start with a weaker weapon: heli + startshooter if i play against ground tanks, for example)
- enable to see life bars permantly, it's a bit hard to get used at it but very useful to estimate your chances [(attached a screenshot how to do it in my version (which is Deutsch)],
- the teleporter is a useful item, use it to make kills, save you from dieing or, which is better in my opinion, to capture control points or to start raid attacks on the enemy base,
- save spells for killing, useing them for creeping is mostly waste (especially for stuns and ultis),
- a stun can be a great action to start attacking a certain because it 'marks an aim', many people stun late when someone would die anyway, but a good stun makes it impossible to retreat and so leads to death,
- there are very good tips/hints at the Battletanks Wiki, you should take a look there, too (
http://btanks.net/wiki/Hints).