Good Way To Make XP

A good way to make XP to level up your classes is by doing Duty Roulettes once a day. Open up the Duty Finder and it should be the first page you end up on and you can earn extra xp by doing these once a day. Another way to earn a lot of XP once you finish all your daily duty's is by playing Palace Of The Dead. You can unlock Palace Of The Dead by doing the level 17 quest called The House That Death Built

which is located in the Adventurers Guild in Gridania. Once you unlock it you can start a match by talking to the wood wailer in Quarrymill. Make sure you start as the class you want to level up. After you finish 10 floors of it you will be given a lot XP for the class you played as and you can choose if you want to quit or do another 10 floors. Below is a video showing gameplay of it to give you a better idea of what its like. Also if you pre order the next expansion Endwalker you get a set of earings that give you a 30% increase to all xp in any combat class up to level 80 as a pre order bonus which is also very helpful.