I hate to do this but there was an epic line in 'The Wizzard of Waveryley Place@ I know, I know.. Disney eeew. But Alex said something like.... I just act like things are going to happen the way I want them to and most of the time they do. It's a new twist on an old psychology which I believe may be called mirroring... the world mirrors your mood... so if you approach something believing it is going to work out well it will... you smile at people; they smile back, you go in with attitude; you get it back, you frown; they back away... that kind of thing.
As for watching what you say... well you are what you are and those who like you like you for who you are and those who don't like you don't count... so be yourself, always, for better or worse. It makes life easier in the end