Congratulations on reaching Level 120! Now that you have hit Level 120 we recommend looking at our Easy mode page and Talents section to learn how to play at max level. To get yourself prepared for the end-game content ahead, we strongly recommend this Battle for Azeroth Raiding Lexicon/Spreadsheet by Medivh. It is a gold trove of information that will help you when gearing up in Battle for Azeroth and more.
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.
Congratulations on reaching Level 120! There are a myriad of new things to do. The first thing you should do is head to your faction hub ship where you have been doing your mission table quests and footholds to pick up and complete the quests necessary to unlock World Quests. World Quests will provide you an opportunity to grind reputation levels, acquire gear, and gather Azerite. There are tons of new things to do that we will cover in our Level 120 Battle Guide found here: Level 120 Battle Guide