So many of my peers don't make a lot of money, but then still go out and buy a new or newish/used car and put themselves on a multiyear payment plan. "Oh but it's only 200 a month, I can swing that". Repeat for like 3-4 other things and suddenly they're always complaining they have no money and don't know why.
I highly recommend to anyone who's looking to take their financial situation more seriously do two things:
1. Read up on Mr. Money Mustache, a guy who managed to retire at 30. Even if you don't plan to retire early, it's eye opening to realize you don't have to spend your entire paycheck every month: http://www.mrmoneymustache.com/2013/02/22/getting-rich-from-...
2. Check out YNAB (You Need a Budget): https://www.youneedabudget.com/. Takes a little work to start using, but once you do, you'll understand your money in a way you never thought possible.