Rage Pooling: The Most Important Warrior Skill
One of the biggest differences between an average Warrior and an exceptional Warrior is how much Rage they carry between fights.
Your goal should be to enter major pulls with as much Rage as possible.
In dungeons, use the final trash mobs before a boss to build your Rage instead of mindlessly spending everything on single target damage.
The same applies when questing. If your enemy is about to die and there's another target nearby, you don't necessarily need to 
Execute it.
Sometimes the correct play is to finish it with auto attacks and carry your Rage into the next fight.
Lingering Rage makes this playstyle even stronger by delaying Rage decay between combat encounters.
Remember, the objective is overall damage and leveling speed, not squeezing every last point of damage out of an enemy that's already dead.
Dungeon Tanking as Arms
One of the best things about Arms Warrior is that you don't need to be Protection to tank leveling dungeons.
In fact, with sufficient gear, an appropriately leveled healer, and proper Rage management, two handed Arms tanking can be incredibly effective.
Your cleave damage helps establish threat on multiple enemies while also improving overall dungeon clear speed.
The important distinction is understanding when you can afford to play aggressively and when you need to become defensive.
- Use
Demoralizing Shout to reduce incoming damage and establish some initial threat. - Use
Cleave and 
Whirlwind to damage multiple enemies. - Use
Taunt and 
Mocking Blow to recover enemies that escape your control. - Use
Challenging Shout when you need emergency AoE threat control. - Swap to a shield when incoming damage becomes dangerous.
- Use
Defensive Stance and defensive cooldowns appropriately.
A good Arms tank knows exactly how much damage they can afford to take.
You should be constantly evaluating your healer's mana, the number of enemies attacking you, and whether the next pull is actually safe.
Two handed tanking is a tool, not an obligation. There's no reason to wipe your group just to preserve your damage meter.
Advanced Arms Warrior Tips
1. Play Around Sweeping Strikes
Your entire dungeon playstyle changes when 
Sweeping Strikes is available.
Look for opportunities to engage multiple targets, save Rage before large pulls, and line up your offensive abilities.
Don't waste your best cooldown window attacking a single enemy when another pull is only a few seconds away.
2. Pool Rage Before Every Boss
Practice entering boss fights with a substantial Rage pool.
Use the previous trash pack to generate resources, then preserve them rather than wasting everything on unnecessary damage.
This is one of the simplest ways to dramatically improve your opening damage.
3. Don't Automatically Execute
Execute can be an excellent finisher, but spending all your Rage on an enemy that's already about to die isn't always efficient.
Sometimes carrying that Rage into the next pull is considerably more valuable.
Think about the entire dungeon, not just the current enemy.
4. Weapon Swing Timing Matters
Your weapon's swing timer is one of the most important pieces of information you can track.
Understanding exactly when your next auto attack will occur helps you manage Cleave, stance swaps, movement, and Sweeping Strikes charges.
Poor swing management can cost a surprising amount of damage over a dungeon.
5. Use Your Cooldowns Aggressively
Bloodrage, 
Berserker Rage, and Sweeping Strikes are tools you should use frequently.
However, using abilities on cooldown doesn't mean pressing them without thinking. Time them around meaningful damage opportunities and Rage requirements.
6. Find a Healer
I cannot emphasize this enough.
Playing alongside a healer completely changes your leveling potential because you can focus on dealing damage rather than constantly stopping to recover.
A coordinated duo can take advantage of larger pulls, continuous combat, and faster dungeon clears.
7. Keep Multiple Weapons Available
Don't immediately vendor every weapon you replace.
Different weapons can have different strengths depending on whether you're fighting single targets, clearing large groups, or playing PvP.
Ravager is an excellent example of a weapon worth retaining specifically for its multi target utility.
8. Always Have a Defensive Setup
Even when playing an extremely aggressive Arms build, carry a shield.
A quick swap into a defensive setup can save your life during a bad dungeon pull, dangerous elite fight, or unexpected PvP encounter.
Being able to recognize when you need to stop dealing damage and survive is just as important as knowing how to maximize DPS.
Warrior
Arms
Warrior goes way back. I grinded Rank 14 during Season of Mastery, tanked and DPSed every raid through Naxxramas, and have leveled four Warriors to 60 in Hardcore, taking them through every 20-man raid and even some 40-man content. 
Druid
Restoration
Paladin
Retribution
Feral
Protection