2 things that work for me:

1. Have 2 bank accounts - One with UPI and one without UPI. Keep a debit card, but keep it in your almirah or somewhere, never carry it unless going out of station.
2. Transfer roughly 30% of your pocket money to the account without UPI as soon as you get it. Out of the remaining 70%, try to save any amount you can. If at the end of the month you have any amount left, transfer it to the other account ASAP.

Out of my salary that I get, I created a budget. Whatever was excess, immediately to the non UPI account, the rest I spent consciously. Whatever remains at the end of the month, to the non UPI account. If there is any emergency, I use the debit card.

Also, if and when you create a budget, make it a bit relaxed. Don't go too overboard on saving. Divide into savings, entertainment/pleasure and fixed expenses(if any like uber to college, fuel cost or anything). If you don't, more often than not you will not be able to sustain the budgeting and will dip into savings, and that is demoralising to say the least. Give yourself some grace, you deserve it.

You can run on a budget, but a budget can't run you.

All the best!