WoW Forever leveling speed

Short answer: Blizzard has not published a typical time to reach level 60, and the beta level cap was 30 as of the 1 October build. Any "hours to 60" figure you see right now is a guess. What Blizzard has published is a set of XP changes, listed below with the build they came from.

XP changes in Forever

Change	Build	Source
Dungeon quests give 50% less of their extra XP	1 Oct	Blizzard: WoW Forever Beta Development Notes (Updated October 26)
XP from killing dungeon creatures is about 20% higher	8 Oct	Blizzard: WoW Forever Beta Development Notes (Updated October 26)
Party XP penalty is back to the Classic Era rule: calculated per player, and no one gets XP if a party member is far higher level	8 Oct	Blizzard: WoW Forever Beta Development Notes (Updated October 26)
Faster respawns in Hillsbrad, Ashenvale, Wetlands, Duskwood and Thousand Needles	1 Oct	Blizzard: WoW Forever Beta Development Notes (Updated October 26)
Crafted food can give a small XP bonus	Deep Dive	Blizzard: Deep Dive panel recap
A normal creature should take about 10–15 seconds to kill solo	Deep Dive	Blizzard: Deep Dive panel recap

Official WoW Forever image: road through hills screenshot — Image © Blizzard Entertainment, Inc. Source: Blizzard News

Legacy perks that speed up levelling

Most players earn their first Legacy point when a character reaches level 25. There are 65 challenges, and each character can spend up to 16 points (Blizzard: Get to Know the Legacy System). These Adventure perks affect levelling:

Perk	What Blizzard says it does
Well Rested	Raises your rested XP cap and makes rested XP build up faster
Talented	Gives talent points up to 5 levels earlier
Frequent Flier	Makes flights cheaper and faster
Thrill of Adventure, Field Guide, Field Medicine	Other Adventure perks. Check the in-game text for their exact effects

Rested XP and camping

A campsite with a tent and fire — Camping is new in WoW Forever. Image © Blizzard Entertainment, Inc. Source: World of Warcraft: Forever Deep Dive Panel Recap.

A Basic Campfire gives buffs that last 1 hour. You need to sit at it to get rested. Once a profession reaches skill 20, you can add up to 3 profession objects to the camp (Blizzard: Deep Dive panel recap). The 1 Oct build also stopped campfires damaging players below level 5 and made the Boosted Rest debuff icon clearer (Blizzard: WoW Forever Beta Development Notes (Updated October 26)).

Tips to level faster

Quest in hubs and follow a route. See the Alliance route or the Horde route. Classic Era baseline
Count dungeons for their kills, not their quests. Kill XP went up and dungeon quest XP went down.
Group with players near your level. A much higher-level party member stops XP for everyone.
Use the zones with faster respawns listed above, especially when they are crowded.
Eat crafted food and use rested XP from camping and inns.
Learn riding when you can. In Forever you get a mount when you learn riding (Blizzard: Deep Dive panel recap).

Related pages: level cap, flight paths and the beginner's guide.

Sources