I am still fairly new to LR2 and not sure how to best explain things myself, but it might help if you check out these videos:
http://www.kelbytraining.com/player/index.html#124

You can watch the 1st three for free...
I signed up for the monthly plan and it's unbelievable how much I've learned in the last month or so.
(And I'm not getting any kind of referral deal, I just really like these courses and have really been helped by them)