There’s so many variables for “lasting longer” and it’s quite subjective.
Things that I “think” work especially for me:
Fitness - sex is a physically intensive thing, so cardio is good to do etc
No masturbation - it’s a different sensation, don’t get used to it
No porn - desensitises you etc
Just more sex - kinda like riding a bike (exaggeration), the more you do it the better you become and feels more relaxed etc
Diet - healthy body
Also don’t let porn or “stories” distort or alter your perception of sex.
In porn they do a load of stop and starts. Everyone doesn’t fuck for an hour straight.
Just learn to enjoy it, especially if it’s not your OH, nut when you want
I’ve had punts were I felt like superman, going strong and continually for the whole punt, but it’s tiring
Again the above is subjective and my own personal opinion