Check out all parts of the leveling guide:
Part 1) Level 1 - 58 / vanilla leveling guide.
Part 2) Level 58 - 70 / The Burning Crusade leveling guide.
Part 3) Level 70 - 80 / Wrath of the Lich King leveling guide.
Part 4) Level 80 - 85 / Cataclysm leveling guide.
Part 5) Level 85 - 90 / Mists of Pandaria leveling guide.
Part 6) Level 90 - 100 / Warlords of Draenor leveling guide.
Part 7) Level 100 - 100 / Legion leveling guide.
Level 80 - 85Once you have hit level 80, go to Stormwind or Orgrimmar to start the quest chain. Head to Hyjal and start questing there, and complete the quests as fast as possible. While questing, queue for dungeons. Make sure to do each dungeon at least once to get the bonus experience from the dungeon quests.
Upon hitting new levels, keep going to new zones, and do not bother to complete each zone. The basic strategy should be to rush quests as fast as possible without bothering to do non-optional quests and killing more mobs than needed. Use your flying mount to do fly to the objectives and get them done quickly.