I think that's the most efficient way to make money until you get higher paying jobs. (with Amy and Jessie)Early game, this is the fastest/most efficient way to make money:
07:00 go work a shift at the coffee shop (skip minigame)
12:00 again work at coffee shop (skip minigame)
16:00: go home to your room, text dad and ask for money, then text mom and ask for energy boost:
16:00 go back to coffee shop, work another shift (skip minigame).
This will get you $250 a day and you'll finish at 21:00 (9pm) so you can still go on dates or work in the club on fri/sat evenings - but to do that you'll need to spend $10 on 2 energy bars in the supermarket AFTER your 16:00 shift ends.
In the beginning you can keep all the money from the club and not worry too much about tipping the other staff.
then you'll make 250 -10 + 125 = 365 on Fri and Sat.
Once you have a (no spoiler) better source of income you can share your club tips to gain points with Amy.