I'm a self taught tank for the most part(people I knew basically only said "google it" when I asked for advice), I also started my tanking on GLA not long after I completed the 3.0 story. Just from what I had seen, using Flash/Unleash/Overpower 2-3 times depending on mob size, you practically never touch it again until the next pull. That's even with massive AoE going off from party members. It also helps that instead of the standard(as I found out later) "Use your entire 1-2-3 combo on one enemy, then change to the next and repeat", I do the "Every hit you send out, is on the next enemy in line. Only when there is one does it get every blow".
