/follow Furied (My warrior)
/target focustarget
/startattack [target=focustarget, harm, exists, nodead]

That is my macro, bound to my charge/intercept on my warrior. With my warrior set as focus. Makes it easy. I keep the /follow in there to continually keep repositioning him as needed. Playing Fury Warrior/Enhancement Shaman. The /target focustarget is in there to make sure he targest whatever my focus is targeting at the time of pressing it. I've had him stick on old targets before and not update without that line.

I use to have
/follow Fuired
/assist focus
/startattack

But then when I'd press it just to start the follow, he'd turn on auto attack on the nearest neutral/hostile target. Which isn't good when you land at a flight point with flagged alliance afk there that are 3x your level.