Give up on making something original, because it's, like, 2018 and that's how we roll. Take a great old classic like GTO. Replace Onizuka with a boring, generic, unrealistically virgin teacher (seriously, this is supposedly a Seinen manga, but the MC self-identifies as a "virgin for life" for whatever reason). Take students with complex personalities and backstories, and replace them with paper-thin stereotypes that barely hold up to a single chapter. Leave the classroom dynamics roughly the same. Oh, and make it an all girl's school, because virgins need a harem or something.