I don't own a car or house, have no debts and groceries are probably my biggest expense. My clothes are cheap (I just buy simple clothing), my hobbies are cheap (hiking is free, running is free, writing is free), and I have investments that have paid off in the long term. Oh yeah, and I never/rarely go out.
I don't know if I have a 'good' salary (my new job probably doesn't pay as well as yours), but at my last job I could save half of my paycheck every month, and over time that adds up. I would have saved even more if I didn't like to travel... every year I took 2 trips that cost thousands and even though I didn't wallow in luxury the whole time I definitely could have been thriftier. Still, I ended up saving most of my salary every year.
I used to have a job where overtime alone would cover my living expenses so I could pocket my entire salary... and then there was even a point where overtime would cover MORE than my living expenses--THAT was sweet. I did buy some useless crap with it though. I regret that... I should have just donated to charity.
I get that not everyone can choose not to have a car, but if you're making a decent salary and living at home rent-free I have no idea what's going on. Maybe you go out to restaurants, have expensive hobbies or do a lot of online shopping or something... little things can add up. If you're taking supplements or expensive drugs or something, that can definitely do it.
My advice is to do whatever you can to live below your means... not at, and definitely not above. The biggest mistake people make when they start earning money is they start upgrading their lifestyles to match. I'm still basically living the way I did in university when I had just enough to live and that's it.