Hehe, I teach mostly braking and skid control etc, more towards the advanced defensive driving, not so much lines and racing techniques.
That said, it really depends on the corner. There are 2 main lines you can use when cornering, and probably 99% of corners would fit into either of these. There is the (and they are called different things by different people) out-in-out technique, and the slow-in-fast-out technique.
Before I go into either, all corners have an Entry, and Apex and an Exit.
In the out-in-out, the apex is right in the middle of the turn. And the entry and exit are on equal sides of this apex.
In the slow-in-fast-out (also sometimes called late entry), the apex is quite late in the turn, so you approach the corner fairly quickly, brake hard and then apex the corner fairly late, and then accelarate hard out. So the entry tends to be quite late (nearer the apex), and the exit tends to be further away. This technique is more popular nowadays, with cars having better brakes, and more acceleration.
Of course, if you have compound corners (like one after the other, or an S bend etc) then it really depends. Sometimes you purposely take the corner sharper than it is, in order to set yourself up for the next corner. Sometimes different again.
There are many other techniques you can learn too, like trail braking, left foot braking (esp in FWD cars), heel-toeing and using the weight of the car to help it to turn, like in scandanavian flicks etc.
Also depends on the surface you are driving on, and the "attitude" you're driving to! If you want to go doriftor like Initial D then it's a whole different style to "grip driving" like in F1... And with different style comes different techniques...
*edit* all that said, if you want to practice lines, a good way to learn is to play GT3 or similar :)
