If you have picked Herbalism and Alchemy, then here's some tips on Alchmey
Many of the good Alchemy potion recipes are sold at vendors selling Bottles, vials, crystal vials. If the vendor does not have a recipe when you go to him, its likely that someone else has taken the recipe, since they only respawn on each vendor once or twice a day.
The very best Alchemy potion recipes are reserved for factions in your reputation TAB in your character window, such as
Timbermaw Furbolgs
Thorium Brotherhood
Agent Dawn
etc
By working on your reputation with these factions from unfriendly/Neutral to Honored Status, you will be able to purchase rare Alchemy Potion recipes from vendors who appear to you when you reach Honored status, in the camps of the Thorium Brotherhood, Agent Dawn, etc.
Getting to honored allows all players to buy recipes, plans, patterns for a whole range of professions, not just Alchemy