From somebody who has loremaster of all xpacs but DF, i will say this.
Do one zone at a time. In that one zone do quests until you get a partial of that zone given for the zone quest achieve. As in 1 of 5 parts done for that zone. Dont stop in the middle of a quest. Finish it. If you do not have the time that day to finish it then leave the ! for next time.
Write down on paper the location of where you stopped and where the next ! is to start the new quest line.
Burning Crusade was seriously hard to finish when i did it. Back then you had to get quests that are a random world drop start. You dont have to do that anymore.
WOTLK and WoD content was seriously hard for me to complete. I did them in 2018 well after their release.
WoD phasing is messign me up to this day as i try to complete zones on a character that did not have them. I stopped midway in Arak and now pahsing is a mess for me in that zone. I had a GM fix a quest in Arak today who said that the phasing was the issue only to be stuck in another phase on the very next quest. I also need help from a GM with this quest as it simply cannot be completed. I do a ritual in arak and then the NPC disappears completely when the quest is done. No ? to complete.
Do the The Gods of Arak quest line in one go. One go. Or you end up with phasing issues.
So, finish quest lines till they are done for partial quest zone achieve. No hopping around. If you see other ? in the area, take them and finish them as well to stop phasing issues.
Turn in and complete secondary quests first. They are the ones under the first quest. Turn those in first. This is to stop the NPC from phasing out sometimes as the first ones are usually main questlines that can and do sometimes trigger movies clips which can then phase the character out. So you then cant complete the turn in if the NPC disappears.
Get the foam sword toy. So you do not kill targets when you are higher levels. Sometimes mobs need to be hurt and not killed. This is what the foam sword is for. The sword is a toy.
Other than that the achiece can be done. It just takes a lot of time. We are talking about doing thousands of quests. I think it is in the 6000 quest range now. I have over 7000 quests done but i think the game also counts dailies and i hve done a lot of those. But i know it is well over 5000 at the very least.
If you run into trouble just contact me as i have done them all and remember most of them no matter how long ago i did them. Most of the hard stuff you do not have to do now. No more waiting and killing for hours on end hoping your quest starter drops from a kill. Those days are over.
Good luck. You can do it. If you do you are in a very small goup of people who can actually wear the Loremaster title with pride. I do