If you've already read the post explaining that 'yes means yes', then you've probably guessed that 'no means no'.
Equally important as doing what you say you're going to do, is not doing what you say you won't.
If somebody asks you to do something, and you don't want to do it - say no.
However, don't say no, and then an hour later "change your mind". If you do this, than people will never believe you when you say "no". They will continue to pressure and persuade you, believing that you will eventually change your mind.
More than anything, you want people to believe you when you say "no".
If you don't know whether you want to do something or not, just say "I don't know, let me think about it for awhile". The best thing about this phrase is the word "awhile", this could mean thinking about it for an hour, a day, or a year! You've given yourself all the time you need to make a decision without committing to anything.
If you use the world "no" a few times with people, and you stand by that answer, than soon enough, as soon as they hear you say "no", they will believe you. Then you can live your life how you want to, not how others would like you to.
Love you, even when you say "no" to me (which at this point is about forty times a day).
"NO! I will not open my eyes for this picture!"
"No, this is really not my problem."
"No....I won't have these chubby cheeks forever so you better pinch them now!"
"No. I will wear whatever I want before 8am."
"No, I swear there's nothing in my mouth."
"I don't even have to say "no" and I'll still get my message across."