Some pointers on how to stay alive, not that I'd know! :P
This blog will go more in depth of soloing levels, but heres the basic beginning.
Originally Posted by Swampy
Hello! I've chosen to write this guide to help people get tons of kills and having minimal deaths! Soloing campaigns is a fun thing to do if you either capped, or are just looking for a challenge! This guide will give the recomended places to solo. (by me)*
UNFORTUNATELY kill farming was taken away and has yet to be brought back so you cant just freeze your xp and gain kills.