The Barbarian is a melee class first and foremost- and it is sadly also the class in the stickiest situation.
Barbarians’ skills and attacks all hinge on their Strength, and they are the only class that does so. This means two things- first of all, they have far less competition for equipment. Since nobody else really cares about Strength (unless they’re really focused on kitting out their Templar follower), most of the Strength-focused magic gear is relatively useless for most characters. It’s not by any means a complete thing- Strength does improve Armor, after all- but it’s a pretty severe difference. Second of all, they are far less likely to have worries about Armor. A Barbarian can much more easily wander around in under-level equipment, because the Strength modifiers will often make up a lot, of not all, of the difference in Armor rating. While this can be a good thing in that it means not hunting too hard for the right drops, it can be a bad thing as you suddenly find that you’ve run into a boss who’s become impossible for you to beat with your -15 level equipment. So be careful.
As a melee combatant, the Barbarian is one of the two classes that takes 30% less damage from.... everything, actually. Between that and their Strength dependency, the Barbarian is the obvious ‘tank’- the character who runs out into the front of the battle and then just soaks up all the hits while smiting back as much as they can. Sadly, in a game like Diablo III this is both more complicated and more difficult- to the point where you can’t just assume that it’ll work that way. While the Barbarian does have a lot of durability, it’s not enough to let them take all the attention- and it’s certainly not enough to let them just ignore their health level. So don’t just assume you’re going to survive anything you wander into, either.
As a melee artist, the Barbarian’s skills mostly fall into three categories, with two smaller groups.
The first group is skills for killing things in melee. The Primary Skill, most of the Secondary and Might skills, and two of the Rage skills are in this category. These skills make you better at inflicting damage- be it faster, larger amounts, or staggering your enemy so they stay where they are and you can hit them again.
The second group is skills for getting things into melee or getting into melee with things. These skills are mostly Defensive or Might skills, and you want to be able to use these as frequently as possible, since a lot of monsters will either attack from a range or at higher levels knock you clean out of melee.
The third group is skills that keep you going in Melee when you wouldn’t otherwise be able to. This is mostly set to your Passive skills and your Defensive skills.
The two smaller groups are the party buff skills- primarily found in Tactics- and the oddball skills, which are scattered all over.