Well, there's the Improved Toughness feat. It turns out worse until level 4, but after that it's better.
Or of course, an item of CON. Maybe 3 levels of Cleric and take "Craft Wonderous". Make all the stat boost items you want at half price! Ok, that's powergam-y...
Combat Expertise? That'll help your AC, which is the shortcut to surviving. Or go for the Spring Attack feat chain. If you aren't there, they can't hit you.
Archery?
The Duelist class to boost AC?
That's all I can think of right now, good luck!
-Tatsu