The rotation for an arms warrior is quite simple. Keep Rend applied at all times on your primary target. After that, use Mortal Strike on cooldown. When MS is on cooldown, use Overpower as a filler ability. When MS and OP are on cooldown, use Heroic Strike or Cleave depending on the number of enemies. Even though you can play arms, you’d probably have a better time going two-handed fury if you’re dedicated to a two-hander.

Engineering is the one must-have profession if you care about powerful combat tools such as Goblin Sapper Charge, Arcanite Dragonling, and Hyper-Radiant Flame Reflector. It also provides great convenience through Dimensional Ripper - Everlook and Ultrasafe Transporter: Gadgetzan. All of these tools are only usable by Engineers, which makes it the top profession for maximizing your performance in WoW Classic, at maximum level.
The Dedicated Offtank — Arms/Protection 31/20. This build still allows for some oomph when you’re not tanking but focuses more heavily on tanking, with a full 20 points in Protection for picking up some Defiance and Improved Shield Block. It’s still not a main tanking build, but it gives you options for when you’re not raiding or running a dungeon and a lot of Warriors used it in classic. You can vary it up by altering how many points you put in Defiance vs. other talents, like this version that gets you Last Stand, which many tanks swore by.

If you thought your job was done after reaching level 60 and filling out your talent tree, then you’re in for a big surprise! Hitting the level cap is just the first step, because now you’ll actually need to take the time to optimize your character. While a mail agility helm might have worked for leveling because it was all you could find, you’ll definitely want a plate one offering strength.
Travel Time is what you will be doing the most of, thus talents or abilities that increase movement speed will likely have the highest impact on leveling speed.The more important concept is this: Shaving off seconds of downtime between pulls is as valuable as shaving off seconds of In Combat Time. When you think about it this way, Damage Mitigation and Regenerative talents / abilities / stats have almost offensive properties and should potentially be valued equally to stats that increase damage.

Jack of all trades — Arms/Fury/Protection 31/5/15. This build was the meat and potatoes Warrior build of classic WoW. This was the build you picked if you were going to do some tanking, some PVP, and you weren’t the main tank of your raid guild or just didn’t want to have to switch specs around constantly. It does a little bit of everything — it has Mortal Strike for those bosses that had a self heal, it lets you switch to a big 2h weapon (although you don’t get 2h Weapon Specialization) in your off hours, it’s basically the I’m not going to be the best at anything but I can do anything you need spec. There are variants for players who wanted to do more damage — swapping out Improved Thunder Clap and Hamstring for 2h Weapon Spec, for example.
The Armadillo — Arms/Fury/Prot 11/5/35. This was a main tanking build that basically traded away offense for defense. There were too many variants to list, but the biggest wasn’t a variant at all, but was instead this Arms 11/Prot 40 build that traded away the 5 points in Fury for Cruelty with full 1h Weapon Specialization and Improved Taunt. Neither of these builds could generate much DPS — this was purely about threat and survival, and any farming or otherwise playing outside of a dungeon or raid would often require you to spend gold on a respec (no multiple talent specs back then) or to have friends who would come kill stuff while you tanked it.
 ":"  -  Any time a step ends in a ":" instead of a "." means that the next step is part of the current step you are on.  This generally means the next step should be done while working on the current step.  This means every "start working on" or "continue working on" will end in a ":".  But this is used with other occasions as well, so keep this in mind.