1. Fire up the launcher. OK, this happens technically before you log in your character for the first time, but it's an important first step. If you've been away for a while, chances are that you've missed some patches. And even if the patching is fast and easy, you might need to go through the optimization step. So when you're ready to come back to WoW, don't expect to just jump in and start hurling spells; fire up the launcher early when you can to let your computer work for a few hours.
2. Quick, check your bags! Do you remember what you had in your inventory when you logged out? Depending on the nature of how you left the game, you might need to tend to some inventory maintenance right away. While we're not all Anne Stickney-level collectors, you should still refresh yourself on your bag contents right away. Don't miss a single, precious vendorable gray item.
3. OK, now let's see what's up with the quests. If you lost track of what's going on in your inventory, your quest log is definitely going to need some maintenance. Your quest log serves as a good bookmark of what you've been up to in game. Now that you're back to Azeroth, it makes sense to hit the quest log to start putting together your plans.
4. Achievements, the great time sink, are still waiting. In case you were worried that our favorite time sink, achievements, might have spontaneously disappeared, let me be the first to reassure you. Your achievements are still waiting for you, lurking in the dark corner of your UI like an angry lava worm.
Did you have a method for tackling achievements? Were you hitting the easiest achievements first, or maybe going zone by zone? Going back over your old achievements will help inspire you with new plans now. Get an idea of what status your character currently enjoys, since that will form the foundation of the future.
5. OK, this is the scary part. Look at your talents. This is where things can get hairy. While it's been a long time since WoW has suffered truly huge talent changes, it's hard for me to guess how long you, my beloved reader, have been playing. So open up that talent pane, and let's take a peek.
Has anything obviously changed? For example, do you have unspent talent points? If all of the talents seem appropriately chosen, take the time to read each talent individually. Even if all the talents look exactly the same as you remember them, taking the time to read the information will help remind you what everything does.
6. Check yourself before you wreck yourself. OK, so your progression and talents are all safely in place. What about your gear? I saved this part for last because it can so quickly turn into a huge nightmare. Pop open your character screen and make sure you're wearing your gear. Nothing's more embarrassing than launching yourself at a slavering boss mob, only to discover that you're not wearing your undies.
Hopefully, you didn't accidentally delete anything. If a piece of highly beloved gear is missing, open a GM ticket to see if they can help. While item restorations can be a pain in the neck, the GMs could be helpful in setting your character to right.
7. Visit a training dummy. Now's a good time to swing by a training dummy and go through the damage rotation a few times. You're trying to remind yourself how to play your class a bit -- remind your fingers of that age-old muscle memory.
8. Check your guild status. You might've been booted for inactivity, or something strange could have occurred during your absence. Make sure you're still guilded with the people you expect to be.
9. Check your mailbox. Pick up anything that's been languishing in its depths, and enjoy any account-wide pets you might not have picked up on other characters.
10. Check your finances. WoW's economy is wound much higher than it used to be, and you might find yourself strapped for cash if you jump into instances and raiding without enough funds to cover repairs and expenses if you ran yourself dry before you stopped playing.
11. Fix your Thing. What's your Thing? Are you a pet collector? Must you transmog all your gear to look a certain way? If so, that's your Thing. Now that the cogs are all spinning the right way, now's the time to make sure your Thing is going as it should.
Get out there and have fun
The game is pretty flexible. WoW doesn't judge why you left, but it's mostly about getting back into the swing of the things. So now that you're sure everything is back in place, get out there and kill some murlocs!
Visit the WoW Rookie Guide for links to everything you need to get started as a new player, from how to control your character and camera angles when you're just starting out, to learning how to tank, getting up to speed for heroics and even how to win Tol Barad.