So much of British humor is built around a single joke. That joke goes like this: "Watch me be really mean to stupid people!"
This joke is by no means limited to the British, but hardly anyone has the same fascination they have with it. They seem content to explore it over and over. If you have even the slightest talent at dialogue and spite you could almost guarantee to get a laugh just by finding a new situation in which you can have a mean person and some stupid people.
Don't get me wrong. I am a great fan of British humor. But there is also a lot of British humor I can't stand, that may superficially appear to resemble that which I love to death. Bad British humor just coasts on that joke, relying on nothing but it. Good British humor can be made by taking that joke and using it as the canvas on which to paint witty dialogue and wordplay and physical humor.