I do not recommend going for TBC, although I remember Hellfire peninsula to be decent, everything else is rather slow. Instead go for WotLK, Borean Thundra gets you levelled very fast, and then you can head straight for Icecrown at 67, which is also insanely fast, although admittedly has a few elite quests. You can go to Sholazar Basin alternatively. 2 zones should get you 60-80 no problem.

Footholds into enemy territories can be done as you grow in levels and should be completed before reaching Level 120. Take the time after completing your first zone to do your first foothold, or you can choose to complete one as soon as you gather your 100 War Resources which will prompt you to return to your mission table area where the first foothold quest can be obtained. Similar to how your initial zone selection was largely irrelevant, this selection is, as well. Simply pick one and complete it to earn your Mission Table second champion. Send your champions out on missions, recruit troops, and then head back out to quest in your second zone selection.
I liked the little discount for the weekend special. I was used to buying other expansions that included a 30 game time card, this did not. However I was prompted to spend gold I had build up and saved, previously playing the game, and it cost me 117000 gold deducted from my combined characters on my old main server. Big download, so I had to wait to play it until the next morning. Gameplay is different, I was used to the old talent point system, alas I had 10 lvl 100 characters, max level garrisons and shipyard. I did the only thing thinkable without having to take time to vendor unusable items that I thought had meaning. Created the new class. Tutorial started at 98, to get you to 100 with a slow intro back into the game. Auction house prices are pretty high with how long this game has been around. I hope to play more soon, but not like the hardcore grind years past. All I know is I am spending remaining gold saved on biggest affordable bags, and whatever flight trainings to keep me moving fast. Game looks good, no lag, I already enjoy the storyline again.

If you are just coming out of Level 110, you will probably have a number of different Legendary items to choose from. Your Legendaries' special effects will stop working at Level 116, but until then they can be a very powerful addition to help you level up quickly. These are our Legendary recommendations for leveling as a Fire Mage in Battle for Azeroth:
Alpha Beta PTR Classic 1.1.0 1.2.0 1.3.0 1.4.0 1.5.0 1.6.0 1.6.1 1.7.0 1.8.0 1.8.4 1.9.0 1.10.0 1.11.0 1.12.0 Burning Crusade 2.0.1 2.0.3 2.0.4 2.1.0 2.1.2 2.2.0 2.3.0 2.4.0 2.4.3 Wrath of the Lich King 3.0.2 3.0.3 3.0.8 3.1.0 3.2.0 3.2.2 3.3.0 3.3.3 Cataclysm 4.0.1 4.0.3a 4.0.6 4.1.0 4.2.0 4.2.2 4.3.0 4.3.2 Mists of Pandaria 5.0.4 5.0.5 5.1.0 5.2.0 5.3.0 5.4.0 5.4.7 Warlords of Draenor 6.0.2 6.0.3 6.1.0 6.2.0 Legion 7.0.3 7.1.0 7.1.5 7.2.0 7.2.5 7.3.0 7.3.5 Battle for Azeroth 8.0.1

Get exalted reputation with every faction you can. This relates to the previous two pretty directly. Gaining reputation with most of the factions of Kul Tiras and Zandalar will allow them to sell you high-level gear, while gaining reputation with the Champions of Azeroth faction will grant you levels for your Heart of Azeroth, the neck piece where all of your AP is stored.
Anyway both got to 110 at around 50h played. I messed up with my Pal by going to Legion once I hit 100 instead of finishing treasures and bonuses in WoD. All in all, if I picked the best zones and was only trying to level as fast as I could, I would probably could have done it in roughly 40h. Note that it would have a been A LOT faster with a Monk as both Ret and Rogues don't really have a decent AoE until 40+ (45 for Ret and 63 for Rogue I believe). The daily also helps a lot. I know that leveling my Monk before the pre-patch was insanely fast. Might be slower with the changes to FoF, however.
There’s a lot of #content in the new expansion. It’s mostly locked behind a variety of gates, some of which players can’t even control. Warfronts are the best example. You might assume joining a Warfront is a simple matter of opening the group finder. Wrong! Warfronts are only accessible for a week at a time. It’s not precisely clear how often that week will come around (it’s based both on a time gate and on the opposing faction gathering resources) but, as of right now, it looks likely to be available just one week out of every four.
I've hit level 65 recently and have noticed my leveling speed drop really fast, I knew this would happen but I'm just looking for ways to become a little more efficient with questing. Right now I'm zipping all over the place without much idea on what to do first. Would this ruin the gaming experience though? (I'm still planning on reading all the quests for story). Or is there any alternatives with a lower price tag?. Also is Zygor guides actually any good? And lastly, (sorry for all the questions) is using it going against WoW rules?
Professions skills are split between expansions now, you'll have a separate skill bar for each expansion. There are still 950 profession levels in total, just that there is no one single progress bar with 1 to 950 for it anymore. Instead, there are 8 separate progress bars. (The only exception is Archaeology, because it will still have a 1-950 progress bar)
/way commands like /way Shadowmoon Valley:Draenor 50.0 31.2 Ashlei don't work correctly. According to the way TomTom works, this waypoint should be created in Draenor's Shadowmoon Valley. Instead, it will be created in Outland's Shadowmoon Valley. So it seems there is currently no way to distinguish between zones that occur more than once with the same name, such as Shadowmoon Valley or Nagrand.