OP Barb tips?

[OgrimOrcGod]

Howdy! First Post!
I am kinda in a bind. 1. I attend a JobCorps center so most of the Dnd Wikis are blocked.
2. I am currently a level 8 Orc Barbarian, and I'm alreaedy pretty OP in comparison to my higher level party members, I want to become EVEN MORE POWERFUL!!!

What feats or prestige classes would give me more damage and crit, and if possible what should I multiclass into?

Details plz, I will update the thread will my class specs soon.

[The Vagabond]

Firstly: What is your edition?
What is your current character's build? Is he straight barbarian? Damage dealer?
How much do you want to overpower the other characters?
Why do you want to be so OP, if you're already on the higher end of power?
How often does your DM use cover and difficult terrain?

[Troacctid]

Just the standard ubercharger. Pounce, Whirling Frenzy, Shock Trooper, Leap Attack, go nuts. If you still need more damage after that, something strange is probably going on.

[Inevitability]

Take levels in Frenzied Berserker. Buy a wand of Calm Emotions/Grease and give it to a caster, to ensure you won't kill your own allies. That's pretty much it.