'girl's varsity tennis team' - Common app short answer: extracurriculars

Simply intending to enjoy the last year of high school, I joined the girl's varsity tennis team with zero experience. Admittedly, the two-month practice was too short to equip me with the ability to perform the skillful volleys, lobs or slices; however, it did teach me the most essential lesson both in tennis and life-simplification. "Just get the ball back," the coach repeated over and over again. By focusing only on returns and serves rather than the game as a whole, I managed to earn every possible point from my opponent. Similar to life, targeting a certain problem or situation instead of a dozen helps me to omit the superfluous details and have a clearer overview. Hence, with the reduced complexity, the odds for success are hugely increased.

two-months
I'd say you jumped to too much of a conclusion @ Hence.
Maybe talk more about what you learned and make that clearer?
...targeting a certain problem or situation instead of a dozens helps me to omit the superfluous details and have a clearer overview of the situation. ...

Just a possible alternative! For me, it adds clarity by relocating redundant details.
Edit mine please! :)

Thank you so much ! I feel like my essay is too short too, just dont know what and where to add it. :)

if you have some words left, maybe you could add how that affected you as a person.

Add some information about exercises you did that provided you with determination and such.