Angling your tank helps to protect it from enemy shells. First lets cover the Russian tanks. The Main Russian tanks are the T-34 76/85 and the IS-2. Both have sloped armor to aid in deflection. The best position is to angle your tank at either 11 or 1 o'clock.
The easiest way to achieve this is to set your gun to that position before you enter battle. Then when you look through your sights if you are dead on your angle is correct. The Kv tanks can also be angled along with the bts.
For the German tanks: I like to put the panther at 11 or 1. The tiger at 10:30 and 1:30. Note that the panther has sloped armor and the tiger does not. The panzer IV seems to work at 11 and 1. The rest I don't really use. I know how to kill them.