Dugi’s leveling guide is the leveling addon I’ve always used to level as fast as possible. It will show you where to go and what to do in-game, speeding up the leveling process. This is optional though, as the game already does a pretty good job at showing you where to go at all times. The addon does, however, come with a couple of other nice features and perks.
War Mode: War Mode can be turned on at level 30 through your talent window, and will give you 10% bonus XP. You will, however, be attackable by players of the opposing faction, but changes have been made so that all players have a fair shot in a fight and even low-level players can kill much higher level players, and at least not get ganked and one shotted. Note: As of patch 8.1, you can get an additional call to arms bonus with war mode on if your faction is underepresented.
Other methods have been discussed. For example, mods could be crippled. DBM didn't exist back then, and the other boss that did that I don't remember the name of, didn't do as much back then as DBM does now. If our goal is to recreate the experience as it was, then obviously not having DBM would be a reasonable way to accomplish that. DBM simply existing, makes the game today easier than it was. So disallow it. Again, this is completely consistent with the spirit of vanilla. Remember one-button-decursing? That was nerfed. They crippled the capabilities of the modding API to disallow that because it made the game too easy. So what if they cripple it a little bit more to once again make the game less easy?
WoW: Classic is scheduled for August 27 (technically August 26 if you're in the Americas). The soonest that you can play it is starting in May, during Blizzard's scheduled stress tests. To opt-in you must have an active subscription on your Battle.net account. If you do, go to Account Management and select the Wow Classic beta. Keep in mind, there will be level caps during the test. The schedule is as follows:
“To fill our pool of beta and stress test participants, we’ll be choosing dedicated players who meet select criteria from both the WoW Classic beta opt-in and the standard Warcraft beta opt-in. Participants will also need to have an active subscription or active game time on their Battle.net Account. While opting-in to the beta is the primary way to make sure you’re in the running to join the test it doesn’t guarantee an invitation to the closed beta test. We may also consider additional factors such as how long a player has been subscribed to the game so that we have the right mix of players to ensure great feedback toward making WoW Classic the very best experience for the community.”
As you can see, both of the guides contain quite the same features. The only exceptions being Dugi Guides does NOT have Gold Guide but it is a slightly cheaper choice. Also when using Dugi Guides, you can choose the difficulty level for the guide; If you want to level up at a faster rate but with higher difficulty, it is an option with Dugi Guides but Zygor Guides does not offer this and instead you will be forced to manually choose higher level guides if you want to skip the guide recommendation.
Good news if you are leveling an alt and you have Draenor Pathfinder so that you can fly in WoD, the next 10 levels will only take a few hours. Personally, I didn’t have this until recently and I went back and got the achievement and I’m glad I did. Now I can level all my future alts fast by just flying and picking up treasures for a couple of hours.