Just had someone PM me and ask about my macros and setup I was using...

So, here are my basic macros so far.

Follow - follows "party1", or the first person on your party list under yourself. This is generally in alphabetical order. If you have more than 2 characters, you'll want to figure out which party member you'll need to follow (up to party5, if I'm not mistaken). I, personally, made a second action bar above the normal one (called the Upper bar in the Interface options), and placed this macro on it (along with any other universal (aka "not character specific") macros). I then bound this key to "F" for Follow.
/script FollowUnit( "party1" );
/script AssistUnit("party1");
I made this for my mage. This will Assist me (hence targeting the main's target), and cast the spell (in this case Plasma Arrow). At this point, you are already targeting the correct thing, so you probably don't have to Assist on every spell, but it doesn't hurt. So, this would be for all your attacks.
/script AssistUnit("party1");
/script CastSpellByName("Plasma Arrow")
It's really that simple. For class abilities or things that won't be cast on both toons, you'll just make sure you don't have a spell bound to that key (1 through = on keyboard generally). Just like WoW, except for the "language" used in the macros.

I don't have anything complicated made yet, since I only got to level 7, but I'll update my thread as I get into it.