I can more than comfortably live on my salary - I'm single, no kids and still live at home so apart from my car, car insurance and phone bill, I don't regularly pay for anything else but have subscriptions like Spotify and Netflix. I pay for little things around the house, I usually do a top-up shop every week but its never a regular amount of money. I think if I was to rent, do a regular food shop every week, have bills and all that other stuff, it would be a lot tighter and I would really need to watch my impulsive spends.
What helped for me was changing all my direct debits to go out on the day after my salary comes in so I know whatever is left, is mine to do as I please and I don't have that hanging over my head. I never let more than 1 months of wage sit in my current account as I find it makes me feel like I can spend recklessly. For example, if I get paid 2.5k every month and my bills were £500, I know I should have 2k left in my current for that month but if that's not spent by the next payday, then it is transferred into a savings account. Repeat every month.
Another thing, I never pop into supermarkets if I only need a few things I can get at a local family-owned shop. I find at Tesco -or any big supermarket- I get distracted and walk out with tons of snacks and never the thing I went in for! That's easily £30 gone as someone else said. Family-owned corner shops or markets, I'm in and out. Also, tell your friends to stop texting you about clothing sales (unless its amazing, usually isn't!) This was a biggie for me. Same for turning off app notifications. Once the temptation is removed, I feel like I don't need it.