In GW2, you can obtain corresponding less XP when you just kill the monsters. And when you discover a new area, you will find locations with icons. It's the goal of GW2 to complete these quests (namely exploration and adventure) and the fastest way to level up.
Detailed explanation is as follows,
1. Heartsmark the location of incomplete and complete regional tasks. To find nearby hearts, simply explore the map or talk to a scout NPC. Often the task is to kill monsters and water flowers, and sometimes there are also some funny puzzle games. After completing, your XP will increase rapidly! You will receive the quest directly instead of finding NPCs first. Open the mailbox after completing quests, you will find thank-you letters and gold from NPCs.
2. Waypoints(locked, active, or contested). Locked waypoints will be displayed on the compass and map, and approaching the waypoint will unlock it for that character. After unlocking waypoints, you will spend little money for map travel.
3. Points of interest(undiscovered and discovered). These are notable locations within the world of Tyria. Such places are worth visiting for they can often trigger dynamic events or you may encounter NPC for main quests.
4. Skill Icon. There are few differences among weapon of the same level in GW2 so characters' skills become quite important. The only way to gain skill points is to receive challenges indicated on your map by a blue skill icon during the process of map exploration. After completing these skill challenges, you will get skill points.
5. Undiscovered and discovered Vistas. You will gain little XP if you reach there, but there may be particular dynamic events and even treasures. Before each Vista usually lies a jumping puzzle players have to overcome to reach it.
6. Location of a personal storyline task. Just follow these icons and you will complete personal storyline task easily.
7. You can even expect additional bonus after accomplish all quests of the same area.
8. Remember to buy all collection tools (axe, sickle, etc). You will find all kinds of mineral resources in the map which are all with high XP, and mining while exploring.
9. Reach area of the same level of other races and complete quests after the completion of your own race in GW2.