get your archery to 50 very early in the game.

http://www.youtube.com/watch?v=P_2gPgdfQG4

You can do this with quite a few other skills after the companion questline, block, 1h, 2h and heavy armor can all be exploited this way.

You can also pickpocket any trainer after you pay for training. I hope they fix this with the balancing patches.

shshshs

Some call this an exploit.. and I suppose it is. Though it does make logical sense that a follower would give you some tips for free. You being a better archer, for example, could be the difference between you hitting your opponent and your follower's ass, from a roleplay perspective.

Exploitative, but useful.