Well being your first time to Multibox i'm sure most of the played time was setup. Once you get the ball rolling with Recruit a Friend exp its smooth sailing. I hit lvl 60 in 1 day and 17 hours played time just questing. Didnt do any instances because the gear would just go to waste in a matter of hours anyway.

Only thing that might help you is some sort of Guide if you dont know the quest locations. Do not do any collection quests. Only kill tasks etc.

other than that... just remember its not a race.. just have fun blowing stuff up.