When I fly solo on my barb, I focus on HP regen and Lifesteal abilities - The sustain with this skill set is amazing, since most of all the skills have % based lifesteal or % regen of your max HP.
This is a sustain focused with damage reduction build:
This is what I use when I am with my demon hunter duo buddy (mostly Crowd Control abilities since he is the primary DPS)
CC & survivability build:
The main difference is the 3 second taunt, and the stun that pulls enemies towards me so I can get them off his butt, but you can see the other changes I made in my passive skills and runes as well.
Hope this helps some barbarians! I love the sustain build when I solo~ Never go below 60% life :)
Edit: Please don't ridicule my build as I have proven it works, instead you could comment on what your thoughts are on this specific build and maybe give me some constructive criticism.