Assertive people are held up for us to admire and yet though we try we don't REALLY like the brash abrasive feeling of putting ourselves first and not really being interested in others. So we go around moaning that we should be 'more assertive'. Actually we should be more curious. People who want to be assertive often lack the means to effectively get attention- that is one point, and this blinds them to their main stance which is a basic lack of interest in others. If you get more curious about why others think as they do then they will be more interested in you. Giving and getting attention- the basis of civilisation as Idries Shah puts it in his documentary 'One pair of eyes' (well worth seeing- you can find it on Youtube). Switch from a general stance of 'I already understand' to one of 'help me to understand'. This doesn't require endless questioning (which can be mechanical and empty) - all it needs is observation, which has verbal and non-verbal parts. Once you really understand someone they will tend to find reasons to listen to you.