A couple of hidden gems:

git diff --staged (shows the diff between the last commit and what you've got staged, great when what you're staging is finicky, lets you double check that you have precisely the files/hunks you intended)

git log <file> (git log, but for just commits where <file> was touched; saves pilfering through all of git log, especially useful when the file only gets modified infrequently)

Random tip: when using git add --patch, try the 'e' option if you need more nuance than the hunks git provides (it contains instructions for how to ex/include individual lines, so you don't have to remember how to do it).