TIPS:
When your not moving, turn your engine off so that way you can hear the direction and how close an enemy gv is from you also, they cant hear you ( I always kep mine off when not moving or when trying to be stealthy.)
Tank Position: I always try to have the front of my tank facing the enemy tank to help improve chances of surviving a hit. I also try to keep my turret facing strait so I always know where it is. (NOTE: some times it is quicker to turn the whole tank using rudder then swinging the turret all the way around, also a combo of swinging your turret and at the same time using rudder in the same direction while in your gunsight to turn around quickly works well. I do that alot in tigrs because of its slow turning turret and it works great.)
Where to hit em?: Hitting an enemy tank in the rear is usually the best spot, however at close range(800-) a good solid hit to the front almost always gets a kill or disables there turret. (tigrs are the exception as there is a rather good chance of them absorbing the hit.)
Ranging: practice practice practice. Also make full use of the z (zoom) key and [ and ] key as those allow you to zoom in further. (I played a whole year till I found out about [ ] keys lol.) I personally have my gunsight zoomed into the bottom of the red line under the "32". I zoom out to take longer shots and will occasionally zoom in closer then 32 to identify if it is a tank or a building I see off in the distance.
Always know which way your turret is facing.
Also I like to position myself up ontop of hills to have a higher vantage point and be able to have a view on the surroundings better.
If you are exchanging shots with another tank and you feel he will hit you on the next shot then, start up your engine if its not already on and after firing your round move a few feet in any direction and get off another shot as chances are his shot will miss.
I hope this helps and good luck.
(edit: I may of repeated some tips others said.)