Years ago I was blowing through money which was absolutely crazy because I had cheap rent and a great scholarship. I started looking at what I was spending my money on and it was very clear that the food I was buying was killing my budget, at that time it was my non-existing budget, but I saw that as a single person I was spending around $500 bucks a month on food!!!
It was also at the time of realizing this that I was about to do a two year service project and during that time I would only have $120 a month to spend on personal items and food. I quickly learned how to save a lot in a grocery store and not care about name brand items. I also found out that it is smarter to buy bulk items and cook those bulk items in a variety of ways so you don't go crazy eating the same thing everyday. Then you put what you make in containers and take your own lunch to work so you stop spending money everyday on lunch.
When I was done with this two year service project I wanted to try my best to continue to only spend $120 a month on personal items and I knew that wouldn't happen unless I started paying attention to what I was buying. This is where my actual advice comes in, MAKE A SPREADSHEET! Make a spreadsheet and keep track of food, personal items, wants (things you bought that you didn't need, for me it's usually clothes), and living expenses. Once you do this you see very quickly where you are wasting your money and you start adjusting your lifestyle to where you need to be financially. Saving while you're young is not impossible, it just takes self control and a plan to achieve your goal.