Being assertive is awesome I actually did a course on it at work. It was the little things that helped such as trying to change your language when confronting somone with a problem. By this I mean saying "I" instead of "you". For example I feel that this happened because ..... as oppossed to you Why didnt you do this .....
:) That's a good skill to learn stick!
I was actually about to write the same as you, @stickchumpion!
I believe that kids tend to be either aggressive, or passive, and as we grow up, we hopefully learn how to find the balance in most of the situations.
I also think that assertiveness is something that comes with practising. It is important to say 'no' when you really mean 'no', and to stand the unpleasant feeling that comes with it. It is also important to build courage to express your real emotions, and to ask for things proactively instead of just expecting from the others to sense what you want.
I agree asking for things proactively is the key , the worst is passive aggression where you get annoyed cause your work colleagues cant mind read.