Something awesome that might bear getting added to the information at the start of the thread (if possible).
A teamwork feat called Blades Above and Below. It's from Inner Sea Races and requires a bab of +6. As long as you and your buddy (animal companion) are threatening the same target and different sizes, and the target is one of those sizes, you count as flanking.
Especially for a Hunter who picked Outflank as your precise feat and then give this through Hunter Tactics, it's a pretty potent feat.
I've got a Rogue/Hunter/Cavalier who's sharing it with his mount to get nearly permanent sneak attack.