Brian Zwahr over at Dev and Such shares a very useful tip. Very often you're in some buffer such as
*HELP* and type 【q】 to quit the buffer. This, however, merely buries the buffer. Most often you want to get rid of it entirely. It turns out there's a way to do that: instead of 【q】, type 【z】. That will delete the buffer entirely.
Sadly, this doesn't work with Info, which is where I most often want to delete the buffer because they tend to be large. Even so, this is a very useful thing to know.