Experience in Guild Wars 2
I've talk to a lot of gamers that says that they level up so slowly in guild wars 2 and so of them complains a lot about that aspect of the game.First and foremost, I would like to ask everyone to simply chill, there's no reason to rush to end level (level 80) because the game does not have a specific end game like many other MMORPGs have (for example World of Warcraft). You will enjoy the game much more if you take the time to look around and explore this fantastic game world. This is also how you get experience. Those who think that they get too little are usually the ones who just runs from heart to heart and maybe do a few events here and there, then feel that they should be able to go into the next area. It does not work that way!
I will list down below what will give you experience in Guild Wars 2 to help you understand how experience in GW2 works.
Killing monsters in Guild Wars 2
This gives the least amount of experience, with one exception which I will take up later in the list.
Renown Hearts - Heart Quests
These are the static assignment zones that give you a couple of different things to do to fill a meter. "Kill X, get Y, find N and give me Z" can be about what is in the upper right corner. Do not look at them as something you need to quickly run and to finish, they last forever and are usually automatically completed when you do an event nearby. When you complete a heart, you can always go and talk to the person you helped, they get karma vendors and you can buy some fun trinkets / recipes / weapons / equipment parts in them.
Dynamic and Meta Events
The large main focus in PvE, what makes the world a little more alive. These pop up here and there and you can find them on your map or mini map if your near enough. Many of the events are part of a event chain, I would really recommend you to stay after you finished an event, most of them leading to several new events within a minute. The events are also always great experience.
World versus World
You level up just fine in this PvP battleground. There's so much you can do here to get experience, join a huge zerg (large group of players) and take down a keep, or join a smaller group and take down some supply camps, everything is great experience and there's also so awesome loot to be found here.
These pop up about every tenth level, starting at level 30 (and with three at lvl 80, max level). Everyone has a story mode (easier) and an explorer mode (harder, and with three choices). With eight dungeons and four different "versions" of each, there is a lot to do here!
The choices you make during character creation affect the personal story you will be playing and the whole gives a great bunch of experience.
Crafting gives a great bunch of experience, especially if you use the experimentation function with your materials.
Collecting all kinds of materials provides experience.
Daily Achievements - Every day you can get an extra amount of experience boost, plus an exciting extra thing if you can handle the daily challenge located at the top in the achievement list.
Exploring - Finding new zones, waypoints, points of interests, vistas and other gives a fairly large amount of experience. It can also run on hidden jumping puzzles that provide a achievement at the end (and thus exp). You can also find enemies who lived long, and the thing is that the longer a creature was alive, the more exp you get for killing it. So it is clearly worthwhile to not only follow the beaten paths!