On the list of things I always Google, is how to create a symbolic link under Linux. I just can't figure out a way to remember what comes first; the source or the destination. The man pages add to the confusion by calling the "source" the target. So, the rule of thumb I now follow is cp or mv semantics.
Here's how I finally memorized it: ln has a 1-file-argument invocation, so ln -s ../../a_fine_file will create a symbolic link to that file under the current directory and under the "a_fine_file" file name. The single argument case has to have the file you want to link to as input. That generalizes nicely as the 2-file-argument invocation maintaining the logic.
A guy in the office always remembers it as remembering that wedding saying - something old, something new, something borrowed, something blue. Whenever he did a symlink he would always say out loud something old, something new, ... That has stuck with me as well for all these years so I've never needed to figure out which was which, I always just knew it.