there are several keys you can use without using macros in game.

1. one that makes you target the current targets target
2. and two involving setting a focused target and snapping back to said target.

I use those so I don't risk using macros. macros are typically very situational and often times respond poorly when their needed the most. I use the above keys to focus my tank so I can dps freely and then snap back to him when needed. that and I use the keys to target his target when I need to.