so some tips please!?
Mr President, there are no official tips.
you have a big chance that the one picking up won't be a genius.
If not completely stupid, you inquire about different products (if she wants to transfer you, you say please not).
After about 1 minute of fast talking, having touched about 5 different topics, you ask what you wanted to ask (her head is supposed to be spinning by now).
If done properly, this should knock her off balance, and pretty much everything goes smoothly hereafter.
If it starts to sound negative, you say that you spoke to Mary* (thats what I wrote down at least last time you tell them) who promised you so and so.
* please make up different COMMON names.
PS: I am not going to make calls for others, if it works with my lousy accent, you should be able to do it too.