I can't really advise on arbitrage, I don't know that much about it as yet.
I do, however, know from AdWords and AdSense issues.
The best resource for learning about AdWords is the
AdWords Learning Center. It breaks down all or most parts of AdWords into easy lessons, that you can either take in a flash-based CBT mode (with accompanying audio) or else plain text lessons. At the end of every section, there is a quiz, if you want to take it. It gets updated all the time with new stuff - much more often than the AdWords Help files themselves. It was created as a preparation tool for those of us who became Certified Google AdWords Professionals, but anyone can use it. It'll take you a couple hours to go through the whole thing; only you can decide if it's worth the time. I think it is, in fact, I'm a GAP twice over, and I still go through every lesson and quiz at least three times a year, just to keep fresh. (There is some stuff in there that won't be useful, like invoicing in other countries, and VAT if you are US based, but you can ignore that stuff if it doesn't apply to you) It's FREE, all it takes is your time. Use it.
http://www.google.com/adwords/learningcenter/
The other very useful thing is the Google AdWords Seminar. If one comes to your area, GO. It'll be the best $300 (the price the last time I took one) you ever spent. I got all kinds of information I would never get from Google themselves; I started using what I'd learned THAT SAME DAY and made money from it. Heck, if they come back to Detroit, I'm going again.
Also, when you sign up for a seminar, they give you a $50 credit voucher for your AdWords as well, so it's really only $250 (or at least it was - check the site for latest pricing)
To find out if there is a seminar planned near you, or to request notification if they come to your area, go here:
http://services.google.com/ads_inquiry/awseminars