For me, I found the best thing to do is just blow off stat raising until you get the boy you're chasing to be your crush. Spend every day with them and call them every night once you have their number and spend every Sunday taking them on dates. You can become friends with the others after you get your boy to be your love. I did with Shiba and got him as my lover by June and I'm doing it with Tocchan and got him by July.