We found this interesting guide on Gameloft forums by  ”pcm2a” at this page, and you can use it and learn something We think that this might help some of players between levels 40 and 50.  Forum member is note down all of the names, daily quest locations, and amount of XP. We assume you can do these quests forever….all the way to level 60?
Do this each day for a total of 83100 xp a day. Pcm2a is not include #9 and #10 since they provide no xp while killing mobs and take too long to complete compared to the xp.

1. Saithion Coastwalkers – 11000
2. Ankar Nomads – 11500
3. Shell Necklaces – 11250
4. Demons Blood – 10500
5. Demon Loot – 10500
6. Keeping Roads Clear – 10250
7. Resistance of Eristars – 10000
8. The One’s Legacy – 7600
9*. Before the Front Lines – 4375
10*. Didn’t mark this fish quest down – 4500
P.S.

We found for you some more info:

* “Red apples” daily in Eristars temple is repeatable
*  Eversummer port has a daily which gives ~5k xp
*  Camp of Hermir has a daily which gives ~4k xp
* Spot for a daily. The crimson badge witch is south east of daily 4 which gives about 11k xp (Thanks Çreed)

These 4 you should do daily in addition to the desert ones for additional xp!

Enjoy…