Do you have some old receipts? If so you can go through them item by item to see how much stuff on there isn't something you technically "need". i.e. soda, ice cream, chips, energy drinks, etc. I'm not saying don't ever get a treat for yourself but maybe you're spending more on these things than you realize.

Then, like others have said, consider switching to off-brand foods and "shopping deals" i.e. I usually get broccoli but asparagus is on sale so I'll get that this week instead.

This is kind of related but depending your housing situation maybe consider starting a veggie garden. I've always thought it would be cool to have a salad for dinner made from veggies I 100% grew myself but sadly I have yet to do this V_V