Leveling up slowly? Nah. That's really about it. Make sure you're receiving the quest rewards on the right hand screen just under the mini map (they're all in green text if you can receive a reward). other than that, it's a slow grind to 50 You don't really need to buy anything with your diamond so you might as well recharge your stamina with it. They have each quest go for 30 days anyway so you have all the time in the world to lvl before it expires. Just don't forget to do it whenever you get the stamina