So I discovered that if you level up the girl’s affection level (親愛値) to level 11, you get a rare gacha ticket (レアガチャ券) for sure.
So the first order of business is to raise every girls’ affection level to level 11!
You get potentially 20 rare gacha tickets if you have gotten all the girls.
So basically, what you want to do is to keep substituting the girls out once they reach level 11, with another girl who is yet to reach level 11.
Then win Battles (対戦) (You can do 2 battles every hour) and Mission (you need to defeat the enemy at the end).
You may be worried that your team becomes weaker because of the substitutions. Actually, for the strong girl you just substituted out, you can replace her main card with her weakest card and take off her sub card. This is so that the new girl can use the strong girl’s strongest card as her sub card (potentially huge stat boost).
Is this whole endeavor worth it? I guess so, I actually drew a Super Rare card from the rare gacha ^^
The girl instantly changes from my weakest girl to strongest girl ^^;
P.s., If you’re starting on this game as well, I would appreciate it if you use this referral code: dRxtDTR0RY21x . You’ll get 5 rare diamonds (in-game item) while I get one ^^