Preface - I haven't played WoW for any length of time since quitting at the end of WotLK. I dabbled in the next few expansions, where it seemed gold was overabundant, not sure if that's what killed the gold farmers/gold bots/sellers, but I didn't seem to see any, or even think I might have a use for them. However, with WoW Classic, I can see a market for them to come back. Did Blizz ever put something in the game to eliminate this after WotLK, or was it the gold abundance that destroyed their market. If not, I see the gold sellers and websites coming back.

You can’t go wrong with a mage. In fact, Mage was the most popular class in World of Warcraft: Classic due to their ability to farm with ease. Back in the day, the player majority even leveled mages as alts in order to gather gold quickly. In addition to their monstrous ranged DPS, mages also have tons of useful utility. As a mage, you’ll be able to conjure food and water, place portals to the major cities, and even earn gold from doing so.
Through out the game, the quest log will be capped to 20 many times.  The guide makes use of maximizing the total amount of quests you can accept at once.  Because of this it is important to follow the guide exactly and only accept quests if the guide tells you to so you won't run into issues not being able to accept a quest.  If you do accept a quest that is not listed in the guide, write it down because you may need to abandon it in order to keep following the guide if your quest log is full.
Greetings! Development of World of Warcraft Classic is underway, and we’re very excited to share some of the challenges and solutions we’re working on. As we mentioned last BlizzCon, the process of restoring the classic game is not straightforward, and it’s important to us to take the time and effort to get it right—this includes poring over numerous game versions, data, and code; meticulously scrutinizing all the changes we’ve made over the years. Rest assured: The WoW Classic team is hard at work making it a reality, and we’re at a point in development where we’re ready to share some of the things we’ve been working on.

Step-by-step class guides are on the way!  The 1-12 Mulgore Guide is the first guide to get all the individual class steps.  At the top of the guide, simply select which class you are playing and the page will dynamically update all the steps in the guide for that class (both text and images).  The rest of the guides will be slowly updated overtime to include all the class steps, but you can see how it's going to work with the 1-12 Mulgore.  I want to thank crazyK and his Placeholderguild for helping me out with the individual class content.  They are allowing me to get the 1-60 Alliance guide done while also getting all the class steps done at the same time, so everything can be ready for Classic launch (hopefully).

One player said in a comment posted in response to the list, “Yeah people don’t realize the sheer enormity of game system evolution WoW has gone through since release. I’m not the biggest fan of BoA by any stretch, but I’ve played since closed beta vanilla, and I doubt I’ll be going back to classic. Leveling was painful. Experiencing these old systems once was enough.” 

For classes who rely on energy regeneration such as Rogues, things have also changed significantly since the classic era. Regeneration used to occur in chunks based on the server “heartbeat.” So, to gain 20 energy, it would take a full two seconds. Today, the system is smoothed out so that that 1 energy regenerates every tenth of a second. This difference changed the timing of being able to use certain abilities. What seems like a minor convenience today actually changes the very flow of combat rotations and burst capabilities in classic gameplay. We felt this was important to restore to provide this authentic experience.

Another hurdle we had to overcome was how to store and merge our data. World of Warcraft has multiple updates or patches in development at any one time, each in a different stage of development. If an art asset or terrain file is added to one patch, the system is designed so that it also automatically shows up in later patches. This meant that If we had simply inserted a new patch for WoW Classic into the current development environment, we would have overwritten things like the current broken dam in Loch Modan with the previous intact version—and as you can imagine, this would have caused issues for Battle for Azeroth.