The barbarian class in Diablo 3 is the same as the warrior class from World of Warcraft, can use melee weapons, axes, swords, spears, daggers, 1 handed, 2 x 1 handed, 2 handed weapons or 1 handed weapon and a shield.
It has some fun abilities like Leap (heroic leap from World of Warcraft), “Furious Charge”, some sort of Charge like the one from World of Warcraft. The thing is that these fun abilities will come to the price of not using the best abilities for your playstyle.
If you level a barbarian, you can either make it a tank, stack vitality which is the most important stat for this class in normal mode when you are leveling from 1 to 30. Damage is not very important as you will still do a good amount of damage with the basic strength you get from leveling.
The primary stats are vitality and strength.
If you haven’t noticed yet. Keep left of right mouse click in order to keep attacking a target, there is no need to click multiple times. Your character will auto-attack the target while you keep your finger on left mouse click.
Other abilities like Whirlwind will also only work if you keep the mouse button pressed.
2 x 1 handed weapons or 2 handed weapon?
You can spec your barbarian for 2 handed weapons taking the most fun abilities and switch to 1 handed weapon and shield when you see you can’t survive too much and a bunch of mobs will put you down too often.
For 2 handed weapons, you should take these skills for leveling.
1. Primary. Bash, Onslaught.
2. Secondary. Seismic Slam, any of the runes. Shattered ground is recommended.
3. Defensive. Ground stop, Deafening Crash. You can get Ignore Pain later mostly for boss fights.
4. Might. You can start with Ancient Spear and soon replace it with Furious Charge once you get it.
5. Tactics. Threatening Shout for more defensive. Any of the runes.
6. Rage. Any of them in the order you get them. On higher level, Wrath of the berserker is a good choice.
Start with Pound of Flesh or Nerves of steel. Inspiring Presence, Animosity. These are the best passive skills for a 2 handed weapon barbarian.
Once you see that enemies can put you down too often, you can spec for a tanking-healing spec.
Tank spec, 1 handed weapon and shield, skills and runes.
1. Primary. Frenzy and Triumph rune.
2. Secondary. Rend, Blood Lust rune.
3. Defensive. Ground Stomp, Deafening Crash.
4. Might. Revenge, Revenge is Mine or Retribution runes.
5. Tactics. Falter rune.
6. Rage. Same thing, Wrath of the berserker.
Nerves of Steel (tanking), Bloodthirst (life steal, tanking), Tough as Nails (increased armor, tanking).
As you can see, the 1 handed weapon and shield spec and passive skills will make your barbarian to attack very fast, survive high amounts of damage and be able to heal himself.
This spec can be switched also for boss fights that are not dps fights, your character will still take a good amount of damage and you might not survive.
These specs and tactics can be used to finish the game on normal mode, you will reach level 29-33. If you play in public games or with your friends, you can choose the secondary spec, 1 handed weapon and shield if you want to act as a tank.