Research your professional value and have the courage to go after it if you are not being paid what you are worth.

I worked 17 years for the same company. I was promoted 4 times during those years and received a few extra pay increases along the way, but I was underpaid as soon as I took the first promotion and the gap increased with each additional promotion. I probably walked away from more than $100k in lifetime earnings, plus interest, by sticking with the company.

I should have changed companies at least once and probably twice. You don't have to be on a promotion path to run into this. It could be you were underpaid on day 1, but you needed the job or you didn't have experience. That's fine, but once you have the experience and have proven yourself, find out what the market rate is for your role and ask for it, be ready to show your research. If you don't get it, start applying for other jobs.

Don't be afraid to talk to your peers about salary. If you are making less, you know there is a gap you can go after (just don't name your coworker when you ask for more, do market research and make it impersonal/just business). If you are making more, pass this advice on to your coworker.

If you are being paid fairly for the work you are doing, but know you can do more, start looking into what it takes to make a move. For example, you might be the best fast food or retail worker the world has ever had, but the job only pays so much. What else might you be good at? You could look for training in a trade or try to find an entry level role in a company that has a wider set of tasks available that offers a growth path.

I agree with a lot of the comments here about saving and investing and keeping expenses down, but growing your earnings is typically easier than shrinking your rent. It still isn't easy though, especially if you need to relocate to earn more.