Once you've broken that habit (and exulted in the resulting fattening of your wallet), look for other, similar leaks. Some examples would be a sport that happens to practice or compete on payday nights, or some charity that happens to need you at that time. So, set up a different habit for that night, one that both involves the obligation of going there instead, and other people who will expect you to be there. Nice idea, but that might still be too hard to do - if you have a habit of going out with them on payday, then this has become your community, and you will feel the loneliness of not going out with them, as well as the social pressure from them to do as you've always done. So, what about making a rule to not go out on payday?
So break it apart: first thing is the one example in your question - you go out on payday with friends/coworkers, intending to only buy a couple of beers (alcohol lowers willpower), and end up blowing through far more.
"Be more sensible with my money" is nebulous, vague, and large there's no place to start. Since willpower is finite, break down the problem into as many pieces as possible, then address only one of those pieces at a time. Willpower is both a finite resource AND a resource that can be increased - like muscle strength. As others have pointed out, it sounds like the problem isn't the accessibility of your money, the problem is willpower.