You have the most basic choice first, hardware boxing or software.
Another basic choice is how many accounts are you going with.

Once you have those two answered, decide which method you'll use for assist.
You can have all toons assist your focus, or assist the current party leader.
If you're using Keyclone to software box, you can use hotstrings for a FTL (Focus-free, Target-free, Leader-free) assist system.

There are a lot of threads for these options, search is your friend.
I'll strongly recommend the addon Jamba, in the macro/addon forum, whichever way you decide to go.