I'm playing two druids, and these are some of my macros I use. I use MacroTalk addon, it's an addon that gives you more options to add chat into macros. The name I gave the macro is in qoutes

[code:1]
"Assist"
/assist Focus
/optgroup [target=focus,exists] Assisting %f, Everyone fight as one!!!

"Focus"
/focus target
/optgroup [target=focus,exists] I got your back %f.

"Follow"
/follow Focus
/optgroup [target=focus,exists] I don't know about you, but I'm following %f

"HealFocus"
#showtooltip Healing Touch
/cast [modifier:ctrl,target=focus] Healing Touch; [target=target,help,nomodifier] Healing Touch; [target=player] Healing Touch;

"MotW"
#showtooltip Mark of the Wild
/cast [modifier:ctrl, target=focus] Mark of the Wild; [target=target,help,nomodifier] Mark of the Wild;[target=player] Mark of the Wild;

"Rejuv Focus"
#showtooltip Rejuvenation
/cast [modifier:ctrl, target=focus] Rejuvenation; [target=target,help,nomodifier] Rejuvenation; [target=player] Rejuvenation;

"Thorns"
#showtooltip Thorns
/cast [modifier:ctrl, target=focus] Thorns; [target=target,help,nomodifier] Thorns; [target=player] Thorns;
[/code:1]

The basic idea is ctrl + hotkey or clicking performs it on your focus. If you just press or click the hotkey and you have a friendly unit targeted you perform the action on that target. Finally, if you press or click the hotkey and you either don't have anyone targeted, or have an enemy targeted you'll perform the action on your self. Since I use the nomodifer option for the middle case, you can still perform the action on yourself by pressing a modifier. The modifer needs to not be part of the macro.. I.e. alt-1 is the hotkey, you should press shift-alt-1 and it would always cast it on yourself. or shift-1 hotkey, pressing alt-shift-1 would always cast it on yourself.

I decided to make the macros like that as with only playing 2 characters there is a possibilty I will end up in a group, and I wanted to have macros that supported other people. I use multibox and nostromo gamepad. I tend to leave broadcasting on at all times, so when I need an aciton done on just one I either use my mouse or the gamepad for my support character. I don't add the /assist focus before each attack. I decided to just make an assist focus macro, that way my main is able to bring the next mob in while my support character finishes off the first, then start attacking what my main is after it's dead.