I have focus and mouseover macros for the main 2 or 3 things a class I'm playing needs for that (mage; counterspell, sheep, spellsteal), however, I keep having issue with knowing what's going on with the other character, even on focus.
Should I make aura addon triggers for the focus? Should I move the focus in the middle of the screen? Any ideas?
Is it simply a matter of being 'smart and a multitasker'?
well i'd say - simply play more arenas, try to not tunnelvision your target's health and look around, keep track of everyone's position.
you could also fraps your gameplay to get a better overlook over what you could do better, and what you missed etc.
but generally it's just something that takes time
what I do is keep target and focus frame close to each other, and even if I tunnel target frame I'll see focus cast bar
It's something that'll just come around to you really
It's just practise. The more you play, the faster you become. The faster you become, the more time you have to watch for your surroundings. Challenge yourself to watch your focus time to time and learn to see what's happening there.
Focus sheep whenever possible. Don't worry about focus counter spell too much. Do it whenever you see the healer cast, but save it if you're going for a kill.
You only need to spellsteal specific things, like a pal lies avenging wrath, gLos add on will tell you that. For mouse over you only need to remove curse SOMETIMES when dealing with a lock if it's a good move, or if it's a hex always.
Best thing to do is learn to communicate with partners.