Know the usual...try to go as far as possible without getting killed, but been thinking about new odd options: 1) play character until he/she knocks into a shopping cart. 2) never pass up a gnome, regardless of condition ...your craziest ideas would be appreciated.
Get every follower at least once. This would mean shifting your karma level up and down like a fiddler's you-know-what, which would be reasonably challenging in itself.
You could also try walking backwards all the time (no 3rd person view allowed).