4.) Fake it- Faking self-confidence may seem like an ineffective strategy, but this technique will sneak up on you and slowly but surely you’ll become self-confident. By faking self-confidence and forcing yourself to act confident; even when terrified inside, you’ll quickly become used to the experience of acting confident and will “train” yourself to be confident in any area in life, and in any situation.
"Faking" is changing your behaviour.
And this is damn effective !
You will project confidence (even if its a somewhat limited one), and it will project back to you : people may ask you for advice, foind you adult and mature, etc etc.
So, what you look like is how you are perceived. I you smile and look confident, you will be considered as a positive person, and that will become more and more true even for you.