Special mention is the Darkmoon Faire Top Hat and WHEE! buff. While not always available due to the DMF being inaccessible most of the month, if you happen to be leveling when the DMF is running, it might be worth your time to go and get these. AFAIK they do stack with heirlooms, although I have not personally tested it. Fair warning: These buffs do NOT stack with each other, and the hats disappear after the DMF goes away later in the month(unless you only log in when the faire is running).
Some quests in my guide are marked as "SKIP" and colored in red. These quests are simply either too hard to solo or not worth the XP/time and are skipped. My guide will only list SKIPPED quests if the quest is a direct follow up after completing a quest, not one that you have to click the NPC again to get it. If you hover over the skipped quests, it will give info on why it is skipped in the guide (unless that info is already listed directly in the guide text).
Once you have your potions, proceed to complete all the bonus objectives in your starting zone. This should easily level you to 92, where you can proceed to Gorgrond. Interesting enough, for some reason many Gorgrond quests are worth nearly double the experience of quests in other zones. Maybe this is a bug, maybe intended, I'm not sure. But I actually recommend you do all the quests and bonus objectives in Gorgrond. For your outpost choice, I recommend choosing the Gladiators, since they give access to more treasures than the shredder IMO.
Valid pieces for Azerite empowerment are available for the chest, shoulder, and head slots of all classes. This equipment has multiple tiers of that can be unlocked, represented by a series of concentric wheels with icons representing individual powers; as individual powers are selected, they rotate into slots at the top of the interface, activating the selected benefit and locking out the others unless the player pays to reset their decision. Outer rings offer multiple choices, some based around the character's class and specification, others around the zone or circumstances in which the gear was acquired. The innermost circle offers no such options, instead being a boost to the level of the item itself, and thus providing a flat all-around benefit.
Guild Banners. The Banner of Cooperation and Battle Standard of Coordination will increase the experience from kills. They both have a 10 minute cooldown, but when you use one, the other is only locked out for 2 minutes. I was very bad about using these, so it might be worth using a macro to drop them on your first attack against an enemy. Keep in mind you must have reputation with your guild before being able to buy these, so new character may have a bit of a wait before picking them up.