Try it out yourself. Some people react strange to the out of nowhere compliments, but not that they regretted hearing it. A lot of the things I am saying are simple things like "Wow you strike me as very intelligent" "You smile with your whole face" "You have such an awesome sense of style"

Its been really good for me too since a lot of times I meet people and my immediate reaction is to be intimidated since I see so many of their positive qualities quickly, telling them the things I notice about them actually helps me retain my confidence in those situations too since I am the one being a beacon of positivity.

Like with most things in life, putting in effort pays out.