Something I do all the time is drop edit selections on the fly. Rather than looking at waveforms or bar numbers and relating that to what I'm hearing, I just listen. When I want to mark my in point I hit down arrow, when I want to mark my out point I hit up. Some people will see this as basic Pro Tools operation but so many people learn Pro Tools via the mouse, the basics are often the parts which are missing when it comes to keyboard control.
To remember which is which, I think of a tape head coming down onto the tape at the beginning of a drop in (down arrow for edit selection in point) and up again and the end of the drop in (up arrow for edit selection out point).
If you are inaccurate, it's easy enough to shift+drag with the selector tool to tidy up. At least your on the fly edit selection got you to the right beat without having to audition more than once.