I'd use the colon. I would like to give a lecture on the subject: “How To Be Successful in Life”.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
tamguatlayIs a comma needed after “subject’?No, because what follows is restrictive. I wouldn’t use a colon, either, and unless I was referring to a chapter in a book or something, I wouldn’t capitalize the words within the quotes.