Good LAGs don't really call that much. If they do it's usually in position. LAGs tend to raise a lot of hands. They don't get involved that often oop. They prey on weakness like raising from the BU after one or two limpers with a wide range of hands. They know that they can out-play their opponents post flop because they have position and they have taken the lead in the hand by raising.

TAGs on the other hand, tend to have a tighter range and when they raise, they have a pretty decent hand. They are conscious of position, but they rely more on their starting hands.