Best way to get experience for Masteries...
If you’re lucky enough to continuously get good maps then follow an event chain:
http://dulfy.net/2015/11/09/gw2-hot-maps-timer-famme/
I feel like it takes forever too -_- Most of the problems would be solved if they made it like Silverwaste instead of having everything on a fixed timer.
Events and Adventures.
Levi Ironhart, Cassandra Irehart, Lucio Trothart
Discord Gearhart, Naevius Soulhart, Frisk Softhart
Do raids give mastery points? If not they should.
Map exploration actually gives a decent amount of experience, so if you have any alts at 80, going for a completed map on each of them (which you need for the specialization collections anyway) will take you a long way.
Experience boosters also help quite a bit. Get fireworks from the lunar new year, experience boosters from wvw dailies or the laurel vendor, and whatever food and utility consumables you enjoy to speed things up.
Eventually you’ll find it’s not so much the experience limiting you but rather the mastery points. Check your map and achievement log for mastery points that are within your reach. Going for those will also give you experience on the side.
And last but not least, do event chains you enjoy. There’s achievements tied to most of these, often even with mastery points attached, so it’s always a good idea to check your achievemnt logs for event chains you haven’t done/finished yet and play those.