Before you rack your brain for an answer to the question, you might as well flash back to what interests you and makes you doing it all the time.
Would it be reading novels, drawing, watching videos, doing outdoor activities, playing musical instruments, or unwinding in local pubs after work, etc.?
No matter what it might be, you can virtually immerse Chinese learning into routines of your passion. To become acquainted and adept at a new skill requires perseverance, commitment, passion and arduous work, including learning Chinese.
But why is grasping Chinese more like a grind than mastering techniques of playing tennis? The answer is plain as day. You love playing tennis so you hardly nag about it even though routine practice may be dull as ditchwater - you could sweat profusely and knock your head on the ground, and next day your legs may be in agony…but the passion hooks you so you hang in there eternally.
If learning Chinese is indispensable, is it possible to intertwine it with your beloved hobby? The answer is YES. For instance, you could apply the new words and structures you learnt recently into a tennis game. Run through and speak to yourself such scenarios - when a game kicks off, who you play with, where and how long you play, how you feel during the game, who wins the game, etc. The entire cognitive process is to repeat and duplicate your new learning, but not in an insipid way of scribbling words and sentences.
Learning a language is nothing but to communicate so always try to inject the target language into life and make it part of daily activities. Your motivation will be elevated in that way because the excitement gushed out of playing tennis, for example, could be extended till the moment you piece new words and structures together to depict it.
Therefore, Chinese language drills can be filled with excitement, creation and satisfaction. You can refresh and understand your learning better by connecting it with what captivates you in life. By doing so, the target language will be remembered and processed in a more intriguing and perpetual way.