DPS Barbarian Tactics
A couple weeks ago I did a bit of research on how to play a good DPS Barbarian. The following is a summary of my research.
Build Considerations
Maximize your strength. It's clear that you need the most strength you can get to do maximum damage. Remember, you strength bonus is multiplied on critical hits. Strength is increased by a base of +4 (+6 at level 11 and +8 at level 20) when you use barbarian rage and you can use enhancements to increase this by another +4. A Rage pot (or spell from a friendly caster) will add another +2. The Frenzy Berserker line of enhancements gives you Frenzy and Death Frenzy (they stack) which gives you another +2 and +4 strength, respectively. This means you can rage, barbarian rage, frenzy and death frenzy for an additional +20 to your strength! You must make all four of these strength boosting options available to your barbarian. Your strength should also be maximized in the normal way: start with an 18, add your 5 level points, get strength bonus enhancements, use a +6 strength item (and later green steel item) and eat strength tomes. My Dwarven Berserker Barbarian at level 20 will have a base strength of 34 and a boosted strength of 52. That's +21 to hit and damage!
Maximize your constitution. Constitution does a few things that are critical for you: more hit points, longer rages, better saves. As a DPS barbarian your AC will suck. That's all there is too it. Don't fight it; embrace it. As such you must be able to take a hit, or several of them, without having to back out of the fight. Barbarians get more natural hit points than any other class (d12) and you should supplement this with a very high constitution. My barbarian at level 20 will have a constitution of 28 (40 when raged) which will give me +180 HP (+300 HP when raged) for a total of 681 raged HPs. (This is without taking the toughness feat, btw.) Next, you gain 6 seconds of rage time for every point of constitution bonus and this is applied before the extended rage multiplier. As demonstrated in the strength section above, you will be almost twice the warrior when raged and you should attempt to only fight raged. If you're fighting and your not raged then you're doing something wrong. Finally, high constitution gives you the normal bonus to your fortitude saves. My fort. save at level 20 will be 33 unraged and 39 while raged.
Okay, okay, wisdom also matters. One major weakness of this build type is your will save. Nothing sucks worse then getting held in the middle of a fight. Mitigate this by putting a couple points toward wisdom (I started with a 10), wearing a wisdom item and getting will save enhancements. With these tactics I get my will save to 25 and further boost it with Dwarven Spell Defense and Barbarian Willpower enhancements.
Choose a weapon style line. You must either by a Two Weapon or Two Handed fighter. Both have pros and cons which are discussed in detail other places. TWF seemed to have a slight upper hand in DPS until the Epic Sword of Shadows (great sword) came out, which overpower all other weapons and makes THF the dominate choice IF you can get one of these swords.
Power Attack is a must. Power Attack damage is multiplied on critical hits. There are barbarian and warforged enhancement lines for increasing PA damage. Take the enhancements you can fit, but definitely take PA as it will significantly increase your DPS. At low levels you may need to turn it off if you start missing, but at higher levels you'll leave it on constantly.
Be a Frenzy Berserker. I talked above about the strength bonus you get from frenzy and death frenzy, but these are actually not the most important part of the frenzy berserker line. All three steps in the line increase your glancing blow damage/special effects, with is good but is also not the best part of this enhancement line. Steps II and III in the line each give you a plus one to your critical damage multiplier. There is nothing else in the game that does this! You x3 great axe just became x6. That's huge. Oh yea, and when you death frenzy, you get another +1 to it giving you a total of +3 to your weapons base critical damage multiplier. So if you would have crit'd for 200 points of damage, you'd now crit for 400 points of damage. That's huge!
Fighting Tactics
You will have no AC, get used to the idea. At low levels you can wear some mithral full plate (it counts as medium armor) and get by with an average AC. Later on (GiantHold or maybe just after this) the in-the-20s AC you get from this won't be worth anything. Drop armor and wear robes: axe block, death block, fearsome, fire resist, ect. They can be swaped out quickly for any given situation.
Have good weapons. This build is all about DPS so it's important that you have the right kind of weapons. You'll need greater X banes, metaline, fire burst and ice burst. Also favor weapons with a higher enhancement bonus since this damage is multiplied on crits whereas special effect damage (holy, fire, anarchic, ect.) is not. For THF, you'll want to get the Carnifex as soon as possible because of its super wide crit range. Later you'll upgrade this to the Sword of Shadows then one or more Green Steel great axes followed by the Epic Sword of Shadows. The expanded crit range on these weapons equates to tons of damage. I'm not sure about the best TWF choices.
You are not a tank. When I say tank I mean someone who attempts to get and hold aggro from as many enemies as possible. Some tanks do this different combinations of high AC, high HP, high intimidate, high DPS, and high damage reduction. This is not you. While you have some DR, you don't have enough and you have no AC. The healer will hate you if you try to be the tank. Your goal in battle is to kill as many enemies, one at a time, as possible without drawing the attention of any enemies other than the one you are currently killing. This isn't always possible, but should be the goal. One on one your enemies won't stand a chance against your DPS and most will fall in a round or two at the most, giving them little time to actually damage you. But if you let a whole group get on you that could be trouble. So, let the tank (generally meaning any fighter or paladin in your party), go into the room first. Enemies will focus on him while you pick them off one at a time. An intimi-tank paired with a barbarian makes this game easy. The intimi-tank can just shield block and intimidate while the barbarian kills all the bad guys. The barbarian doesn't get attacked and the tank uses DR/AC to minimize any damage he'll take. This tactic is extremely effective if the two builds are up to snuff. The point is a DPS barbarian should try to only have aggro from one enemy at a time.
Get good items. We've discussed weapons and robes above but there are some other good items that you'll want to obtain. The Scourge Choker from the Cursed Crypt can give an additional +8 to strength and constitution. The madstone boots from the Reaver's Fate can give you a +4 to strength and +8 to constitution. The boots also give you a +4 Natural Armor bonus to AC, and a 20% attack-speed boost! You'll want the Voice of the Master and Mantle of the Worldshaper like always. You should also consider healing amplifying items like Leviks Bracesrs (from the Hound) and the Finger Necklace (from Litany of the Dead). You have so many HPs that healers will appreciate this. Minos Legens and Thrane's Googles are also useful. Finally, always carry Rage, Lesser Restore, Remove Curse, and Remove Fear pots. You'll want to drink a rage pot BEFORE every Barbarian Rage to extend the rage by 6 seconds. You'll want to drink a lesser restore pot after each barbarian rage to remove fatigue. (You can also carry lesser restore and rage clickies to accomplish these tasks.)
That's it for now. Do these things and your Berserker will be a joy to play. Screw this up and healers will hate you!