When it comes to levelling the Priest Class from 1-60 fast, XP grinding locations is only half the battle. You will need to make sure your weapon does enough DPS so that you can clear these mobs fast enough, it should also be noted that monster should be around your level to make sure to gain the 100% XP Reward. The Level your character should be before you start that specific location will be indicated to left in a Blue Color for Alliance [Lvl 35-39] and the Orange Color for Horde [Lvl 35-39]. The Mobs you are looking for in that specific area names are Bolded [Mob Name].
Now that you know to loot everything (see tip #1), you’ll have a lot of items in your bags. Any item that is white quality or greater may sell on the Auction House. How do you know what will sell well on the auction house? Trade goods and green quality (or better) items will almost always sell on the Auction House. See our Auction House guide (coming soon!) for more information.
The main topic for Classic at the moment would be whether the game is actually harder or just has more redundant activities you have to do before doing the stuff that's really fun. This is actually a good discussion to have, and not just for WoW, but gaming in general. The main sticking point for now, as most people are on (relatively) low levels is the breaks between killing mobs, especially for mana users. In the beginning it's actually refreshing having to think about what you can and can't pull, not just running into a bunch of mobs and killing them in *insert current optimal time to kill Blizzard determined is the most fun*. The food/drink breaks after a few (or even one) mobs provide time to actually look around the scenery and the mobs you're facing, and while there isn't much strategy involved at these levels, you still at least pretend to plan out how you're going to get to that quest mob without being killed by the 4 random ones surrounding them. Not being able to pull whatever mob you want, and actually having to check what mobs are there when you don't have interrupts yet (casters tend to be a nightmare) is definitely more difficult in a real way than what we have today. As a caster, having to actually think about which spells to use based on mana cost (and perhaps even using lower ranked ones) is definitely more difficult and requires more engagement with your character than we have in modern WoW.
This is something that people really need to start to understand, not just for Classic or WoW but software developement in general. Fixing a bug isn't just flipping a switch or changing a single digit. You have a machine with literally hundreds of thousands of parts, designed by dozens of different people at different times over the course of 20 and more years. You change a single thing and it might break 50 other things in very subtle ways that might not even emerge until months later (i.e. the very high M+ keys some players got at the start of BfA).