All I just did was hug/kiss/grope/flash, some walks on the beach, some dates in the night club, some talking in the sunbed, don't know what I'm missing tbh
OK... Let's start with 3 basic ones. If you're doing all of these, and paying attention, you should probably read the walkthrough.
1) It's not just them, it's you too. The fact that you're on an island of beautiful women doesn't mean that you're muscular, athletic, and have good skin. Your own looks (get some beauty cream and some hair gel), strength and endurance (work out in the gym, talk to Jennifer about how often) are very important.
2) Use your phone, particularly the first option where it shows you the girls. Look at the options. Hover the mouse over the achievements (scenes, events, and appointments). Make sure that hide hints/hide requirements isn't selected (if you see show hints, click it).
3) If you don't have the watch and haven't gotten the codes for the monitor implants, get those (talk to the Doctor on duty).