How to approach boss on a salary increase request?

Hello, I graduated in Chem E from one of the U.S. top engineering schools. Started work in one of the big cities with a M to H COL (high for me, but definitely not as bad as,say, NY or LA). I started with a 75k offer and a max of 5% year bonus based partially on individual performance and partially on company performance. No sign bonus.

In a couple of months I’ll have been with the company for two years.

Problem is that between rent and loans and car payment and food and gas etc. I cannot afford anything.

Company gives yearly “merit” raises in April each year that are really just a cost of living adjustment. Usually you get 2-3 percent (a colleague said), but I got 5%.

So, I am approaching two years, and making 78.5k. My friends who graduated with me are all making upwards of 90k.

To make matters worse, I was late to college so I am currently 28yo. I know this shouldn’t matter, but I find myself thinking that, at my age, I should be making more.

My company doesn’t have promotions and everyone in the group has the same title despite years of experience, so no chance of getting a salary bump like that.

Any advice on how I can approach my boss to ask for more money?

TIA