To earn the next XP level you will need to collect some XP points. Please tap on the shield icon in the upper left corner to see how many points are left until the next level. 

The best strategy to earn XP points faster is to follow quests shown on the left side of the screen.  Then you will get both XP rewards for completing match-3 levels and for completing quests. Here is how:

1 - Press on the quest that asks to find an item. The icons of such quests usually have an image of the item on the icon. 

2 - Press on ‘Do it!’ and it will route you to the building and level where this item can be found. Once you find the item, you will get XP points specified in the quest.

3 - Play and win level on which item image is displayed (it should not blink).

4 - And you will get XP points each time you win match-3 level.

There is an option to increase XP rewards - use spells such as Strength of Experience, Might of experience and Pharaoh's Treasure that increase the experience points you earn.

Following quests you will earn both XP rewards for winning match-3 levels and for completing quests. It will help you progress much faster!