Before reading further, wash yourself the soylent and saltiness of many other reviewers giving an score lower than 5. They're upset because the artist gave a free NTR innuendo on later chapters (around 14-16) but those people can't understand that was a joke.

Please put these on, Takamine-san is one of the recent manga created by Yuuichi Hiiragi, the hype it takes on the firsts chapters is because it's a story about a high schooler boy (Shirota Takashi) that has the worse grades, not popular and in the end your useless main character, now for some reason he likes the best girl at school, Takamine Takane, and for some reason he discovers she has a secret that can rewind the time so she can become the godly student she is.
Story at all is pretty much inexistent, because for some circumstances our boy Shirota becomes "her closet" and everytime she asks he had to put on her some underwear that is part of her secret time rewind power. On the latest chapters you can see there's a reason they're together and not only because he discovered her, but if there wasn't a reason a all the story would go around on them anyways.

Art for most of the chapters is about how perfect Hiiragi can draw her heroine, so most of the time is hard to find an appeal on the surroundings because the focus is about Takamine on a sexy pose, taking off her underwear or wearing some sexy and kinky lingerie stuff. Background characters are some rare to appear on chapters (until the 17th, you can see there's some new character), you'll see most of the time interactions on Takamine and her closet in some ecchi situations, and that's great.

Characters personality are simple about themselves, the classic main character that is useless and spineless at life and for some reason Takamine is helping to grow as person and learning that life is not about having it easy but more about working hard. And Takamine being more of a bossy and perfect character that give us some interesting pace and secret reasons and feelings for Shirota-kun. Interactions are only between both of them, and because of that you'll feel the chapters are stale and repetitive, and thinking the only thing salvaging the manga is the sexy stuff Takamine pulls each chapter as fap material, after some chapters the author is trying to give more than just fan service so if you're still reading then keep it up you won't be displeased.

Enjoyment is subjective and for a monthly release of this story is a nice dessert after a hard day at work or study. I find it a nice short story and by the looks of it is short enough so people can read it later if they miss it.

Overall if you're looking for a manga about some slice of life with some ecchi interactions then Haite Kudasai Takamine san is your pick for a while, and I'd suggest you to get in twitter and follow the authors for some clean Takamine san drawings.
If you're looking for some serious slice of life, some battle manga and / or somewhat stuff like a very romantic story then I'd ask you to find something else.