My hardest 1........Ok guys strat.I usually charge..go zerker stance then use pummel.But the cooldown bites on pummel.ty

I usually fight casters in Battle stance.  The trick is to keep em close, but it always comes down to your health bar agianst their mana bar.  I usually charge and hamstring, this is where improved hamsting can become very helpful. If ur fighting a warlock remember to use death wish or another spell that makes u imune to fear.  Also remember that DoT is usually applied at the beggining of the fight, so u might want to use bloodrage right after u charge and activate ur spell reflect.  I stay in battle stance because I can swith my 2h to my 1h/shiled and cast spell reflect.  The timing for this is very important.  It must be done just before the caster finishes casting his spell so you dont give him time to interrupt the casting.  Just keep using pericing howl, hamstring to keep him close.  If u have over 25 rage I recomend to use intimidating shout to fear them while they have a mobility disbuff.  This allows you to get some damage or if your low on health to bandage. Hope this helps.

along with what is said above jump around like a rouge its helps.

And if its  a noob caster try to stay behind him so he cant cast

I usually stay in Battle Stance as well... You can set up a macro to easilly swap your two hander for shield and sword during a fight for shield bash too btw, but I find it unneccessary... the only caster that I've lost to in a while has been... nothing. 

Intercept is your friend.  Improved Intercept Talent under Arms tree if you go that route can help tremendously.

Charge
Hamstring
Rend
<Crit for Deep Wounds if you have it.>
Mortal Strike when they start to cast a heal if you can't interrupt it.
Intercept when you see a nasty spell that casters use when they are Oh ****** their pants. IE: Polymorph/Entangling Roots and such.
Then just heroic strike em to death. 

^ And what the above guy said about constantly moving behind casters is always great and funny... but I found out the hard way it doesn't work on fear.

EDIT: Just in case you don't know... You can swap to Berzerker stance and retain 10 Rage with Tactical Mastery but you can also use the Bloodrage ability for 10 quick rage and intercept if you need it.

1 - Get Tactical Mastery now. NOW
2 - Make a spell reflect Macro
3 - Keybind your stances.
4 - Berserker Rage breaks Fear, how do you not know that?
5 - Only pummel their main tree. Ever see a Warlock casting Immolate? Don't Pummel it
6 - Hamstring keeps them in range
7 - Mortal Strike is good DPS, use even when no heals are on the target
8 - Use Whirlwind
9 - Berserk Rage also makes you immune to Incapacitate effects