Hmmm if already burnt out as others have said reduce your game time by a lot.
Other than that to avoid getting there my suggestions(which is how I generally play myself) are:
1) vary what you do during your game time - I don't join farm parties, I don't focus on one thing only - I will do a bit of everything as I have time, want to do it etc
2) enjoy what you are doing - while doing something ask yourself - Am I having fun? - be brutaly honest in your response - if the answer is no go do something else
3) I play on the PS4 with the PC screen next to it so I can while waiting for stuff or doing crafting or whatever chat with people elsewhere, browse the web, watch youtube videos, twitch streams etc, even have a 3ds near me if I want to play something there - so will always have something other than the game around that I can refocus on
4) take breaks - during weekends I will often login in the morning and log off late at night - I will purposefully walk away from the game and do other stuff - be it help with lunch, go out for a walk, grocerie shop etc... This way I go from being there 12+ hours to more like 6-8h in total - someone else might just log off and go play a different game for a short time to relax - it's all valid as long as it's a break