Ooo! I forgot to add this one. When I want to leave a mark that I want to be able to find later, I will drop this six-character sequence: ^^&&^^
This is left over from my old VAX/DCL days, where the text editor would insert that particular string as a marker to go back to later (i.e., the keyboard command "insert mark" would just drop "^^&&^^" wherever your cursor happened to be, and "find mark" would go to the next one of these).
--Patrick