Nice article !
The best thing to do after saying Yes or No is to add an argument to make it stronger. No because something.. That way you'll minimize the 'risk' of being confronted.
And, on the same line, usually it's better to offer to the other person alternatives to your first request. That makes it harder to receive a no :). For example, instead of asking "wanna come to X?" you could ask "wanna come to X or do Y ?"
:)) I see in the last part too much NLP (I don't like NLP that much, I think it teaches manipulation over listening and understanding).
Giving arguments of why is a No could help indeed with one condition. We should not feel like justifying our NOs, just making sure the message we send is what we really want to say. When we justify we usually don't trust our NO so much.