Never cheap out on headphones if you use them, the cheap ones never last long, and will end up spending more on headphone in the long run then if you just got a good pair in the first place.
Learn the times when food is marked down at your supermarket of choice, a lot of the fresh stuff is good for freezing. On that note learn to cook, even something like pizza you can save a ton if you just make it your self and it should also taste better.
Don't get Netflix every month of the year, let stuff build up and make the most of it when you do get it, Also lots of free legal streaming with some great movies on there, such Roku, Pluto Tv and others,
Lots of streaming sites give you free trials, such as Mubi and Shudder. Well, you can get those free trials every time you get a new bank card. On the topic of free trials, lots of sites that can help you find them online. I got stuff like a free pub glass in the past when I did that.
Cut soda out, drink more water, cheaper and better for you. After a few months, it will be hard to even go back to soda.
Always look up vouchers codes online, and on that note, join cashback websites.
If you play games on steam, sell those steam cards, may not get much for them but it does add up and takes no time to sell them.
Even if you don't want to use Epic Store, you can find free pc games pretty much every week. If you are fine using Epic Store, make sure to get those free games every week.
Any big purchase, make sure you research the hell out of it. Want a TV, learn what you can about TVs, and each model you are looking at. Do this, so you buy the right one with no regret, and making sure you are getting good value for money. Just because a TV is cheap for 75 inches doesn't mean it;'s good value for money.
Walk to places more, if you can walk to somewhere you really should, cheaper and good for you.
Try and sell shit you no longer use and don't plan to use again.
Never take a loan out for a car if you can, unlike houses, cars are awful at keeping value.