Explore, explore, and explore some more. I've seen a lot of people complaining about the lack of things to do to level, I watch them race from Heart to Heart then complain some more of how the game is unplayable. You’re doing it WRONG. Don't run off the moment a DE finishes, look for the main NPCs of the DE, they may be having a dialogue or may start running off, follow them, wait for what happens, chains don't always happen right away and it pays to be more in tuned with the environment. The mentality of “LETS GO POINT A TO B!” is actually very detrimental to how enjoyable the leveling process can be.
Hearts are meant to guide you and something to do in between DE chains; they’re not the major attraction, go off that seemingly dead end trail and make your way to that Vista, you are rewarded for doing that. In fact, if you make your way towards a Heart and a DE happens, you’ll probably complete that heart too. As you become more conditioned to the dynamic event system, you’ll notice in higher level zones they chain more and Orr (80 zone) does not even have hearts, the main attraction are the Dynamic Events all throughout the game.
Additionally, everyone should pick up a crafting profession and gather. There is no discipline just for gathering, just buy the appropriate tools and you can gather any node, there is no competition for nodes and you also gain XP for doing so. Crafting also gives a CRAPTON of XP, when I hoard mats for a few levels; I walk away each session with at least 2 levels. The first person to reach 80 legitimately pumped out the last 20 levels from mats donated by his guildies. I stumbled into a cave filled with destroyer crabs with a purpose, to gather those damn nodes they're guarding. Deeper into a cave I found a lost little girl clearly NOT CHILL with her situation and well-being. Talking to her triggered an escort event to bring her to safety. This is just one of few examples of how well the world is tied together.
Between your Personal Story, Dynamic Events, Skill Challenges, Renown Hearts, Exploration (Point of Interest + Waypoints), Vistas, Crafting/Gathering, and WvW, it is very easy in fact to always be over leveled before you even complete a zone. If you’re up to it, dealing with content 3-4 levels higher than you also nets you more XP, better loot, doing this is the only way I’m not downscaled as there are simply so many ways to gain XP.
TLDR: Take your notion of leveling conditioned from other games and throw it out, GW2’s PvE plays like a different beast and is immensely more enjoyable when you slow yourself down and be whisked around by the world’s wonders. You miss out on a lot on what the world offers if you just chase Hearts/DE then rush to the next one the moment it’s finished.
EDIT//I realize now the title is misleading and has other connotations to it. I did not think that far when I was first making this post and any impression of trying to run your life for you is unintended. I'm not implying this is the correct way to level, this is merely a post for helping people that still have a limited understanding on how the game is built and what you can take advantage of to help with your journey.