sometimes you are successful sometimes you are not due to who is more desperate: if you appear desperate to buy you will lose. if the salesperson is desperate to meet a sales target he will do anything humanly possible to get that sale.
so you must be patient and have thick skin but be polite and do not piss anyone off
ask nicely, i will buy it for 5k less or something like that - if they say no then say thank you i will look at mr M down the road because he can give me 8k less + tow bar + etc etc for example
sometimes they can't reduce the price much but you can ask for - free servicing, extended warranty, free wof, free tow bar, etc etc
i like the idea of calling other dealers around and see who needs a sales target met :D