When exploring the Maps, do not complete them.
Map experience is based on your level. At 20 you will be awarded 300 experience. At 40 you will be awarded 1500 or so. At 45 you will see closer to 2000. By 49 you have cap possible experience.
It's difficult to play and not go to area's you have never been but it is possible to avoid some area's in each map. The reason for doing this is, when you get the final area on that map it will again award based on the experience tic for the area but also award 10X for the completion.
So if you are 45 and you obtain 2000, you collect 20,000 for the complete zone. It might be tempting to be the great explorer but if you can wait, you will see a high level melt away from the map achievement system.