Jack Daniels:
LOL. Well played sir.
You can also go the referral route. Ive made over 1000 credits just from my referrals (about 90% of those little theafers running around)
Attacking isnt everything.. but it's the fastest way to get levels. I've been pounding on people about 2 levels above me. Once I began having difficulty doing so (at level 8) I stopped and started hitting the gym again. Once my stats are where I want them, I'll continue my climb.