If I create a new org-journal entry, the entry will open with an Org-mode bullet and a timestamp. If I already have a journal entry open though, is there a way to add a new bullet and timestamp from within the entry? I did not see any mention of that, but I figure it would not be very hard.
I press C-c ! to run org-time-stamp-inactive to add a timestamp. That may be bound for you. Preface it with a C-u to get the time in addition to the date.
I understand this question is almost an year old, but since it may help someone in future, I'm adding my answer
M-x org-journal-new-entry does this exact thing for me.
e.g. If I had a file for today's journal with single timestamp bullet (say at
11:00) then calling
M-x org-journal-new-entry next time, will just add new timestamp bullet (for the current time) to the existing file.
Just for testing, I called
M-x org-journal-new-entry in rapid succession (within same minute) so two entries (for say
11:00) were created. (I had expected that it will not create second bullet, but ..)