Best strategies vary from person to person...

But usually, simply stepping away and taking a break is a good idea. You don't even have to go completely cold turkey: ...just, maybe log in once a week to socialize if you want.

But like others have said... focus on some other hobbies or pasttimes for a while. When you're ready, the game will still be here. Just because you're not among the first to complete the new shinies in patch 2.whatever, doesn't mean you've missed out. It will still be here.