A good teacher or an expert is someone who, after listening to you for five seconds, knows :
- what you know,
- what you don't know,
- what you want to know, and
- what you need to know in order to achieve what you want to know.
Hence, if you are offering advice, do take a step back and spend five seconds to figure out what they other person knows, does not know, wants to know, and what he needs to know.