Yeah, as usual, this is very sound advice. If you have confidence, most of the rest will follow. I have to advertise for the second path of gaining confidence, or rather satisfaction with yourself.
First thing, as you mentioned, should be coming to terms with the fact that you most likely are absolutely fine just the way you are.
Still, if this just will not work, e.g. you cannot come to terms with being a bit chubbier than the average male model, you only have one choice left: Change.
Keep in mind, I am only advertising this as a secondary option and you should NEVER change for another person, ONLY for yourself. (Although if you do something mostly for you and a bit to please another person is fine, too. Do not be too perfect...)
And in addendum: Some things of course you cannot change, but that should be clear at this point; if you are 5'3", you will never be 6'2" and if you have a strong attraction towards only other men, you will never be a straight guy.