Looking up things with Vim’s :help command can be error prone if you don’t know exactly how to format what you are looking up. Bypass some of the guesswork by hitting Ctrl-d after writing part of the :help command. This will populate a wildmenu of possible matches.

For instance, if you know there is a command containing ?, but you aren’t sure how to look it up, try the following:

:help ?<Ctrl-d>

You can tab through to the one you want and hit enter to read up on it. Who knew there were so many Vim bindings involving a ?.

See :h help-context for more details.