Making The Grade: A Grading Guide to the Top 50 Most Widely Collected US Coins has colorized photos that show you where to look for the first wear points on different coins. To help you improve your grading skills consider putting together a Mercury Dime Grading Set of coins of varying grades. By using common date coins for the higher grades you should be able to put the set together for a reasonable price.
what hobo said but just make sure its a year with a decent strike......mercs are weird about strikes so you have to figure that part out too
I still don't understand strikes... I just look for luster breaks to differentiate between MS and AU, really... doesn't work that well, but it gets the job done for me, haha.
Conditional Rarities (ie FB, FT, MS68, Cameo, Deep Cameo, etc.) are a ballgame in and of themselves. But most people think of rarity in terms of circulated condition.