Zapallbugs has a decent walkthrough that I had to make changes to which can be found in the OP or the link in the quote below (still new to this lol). When I have time, I would like to edit their file, of course with their permission:
The change definitely needed is Monday you have to sit with your classmates for lunch, since you need the lust point with Laura or you won't have enough for the beach day 3. I honestly just sat with my classmates every day except Friday when I had sex already with my class (as the only benefit for sitting with your classmates would be to spike Quentin with the pills from the drug dealer, but these were just a waste of money and time, I didn't even get them myself.)
Then there was personal changes I made, I didn't visit the old woman at any point, I watched a movie with my mother Tuesday instead, pushing Tanya to Wednesday and Thursday instead (skipping a day of training). I also didn't sleep with Nikki until the Double Delight on Saturday so I more focused on building up Chantelle ("we should all hang" on Monday and training with her on Friday in the school gym, moving Katsumi to Saturday in the morning).