Play to many different things

Master one game while dipping your toe in the others. Like I spend 80% playing NLHE full ring, 10% NLHE 6max and 10% PLO, 2-7 Draw and Razz, which is like my "poker is fun" time instead the "man, this sure is a grind". I still try to play my A game, but it breaks up the monotony once in a while. Plus I think learning other games, albeit slowly, will help improve your NL game.