After thinking things over a bit, I've come up with a few things that I either need to read up on / or have explained to me / or do differently.

1) I need to keep my AC buff running at all times. My normal AC is around 215 and the buff adds another 315 (with an upgrade to that spell at level 20). It lasts for 10 minutes or 20 strikes. Overall, it would boost my physical damage reduction from 10% to 21%. Which would allow me to survive a little longer when being beat on. Last night's wipe was partially caused by me dying while I still had mana.

2) It's possible that the mage had rooted the mobs and I didn't move away from them. So I need to keep my eyes open and back away slightly from mobs that are hitting me every other swing.

3) I don't understand how the meeting stones work.

4) I saw a lot of graphics appearing on mobs or over mobs' heads that I didn't understand. Skulls, red pointy arrow thingys, red crosshairs.