An easy way to increase the speed of leveling up is being rested. This will double the experience from killing enemies only. Discovering an area will not get you double the experience. An easy way to get rested is logging out at an inn. Whenever you know you are going to be away from the game for awhile, try to log out while inside an inn. This will get your player rested while you are away. To tell if your character is rested, look up at the circle next to his or her portrait where it shows your level. A "zzz" will be there instead of your level. This indicates that you are rested. You can also tell if you are rested by looking at your experience bar. The experience you have gained so far will be blue and all of the experience you gain will be blue until you pass the small marker on the experience bar.