In the sense of Vernon God Little.
1. Be a 'yes' person.
Trade little favours with other 'yes' people (in the sense of the 'Favor Bank' in 'Bonfire of the Vanities'). 'No' people are both high maintenance and incur too-high transaction costs to get them to do stuff well. 'Yes' people get the world's work done.
2. You can look stupid talking to lay people
How many times have you discussed something technical with a bright person who knows nothing about the area? As you run an internal translation system to filter acronyms and too-hard concepts, and work on generating appropriate metaphors on the fly, your conversational partner thinks you can't really understand this stuff all that well.
You are then joined by someone else who is also an expert. You switch gear - now you are motoring! Your original conversational partner is amazed: they now have no idea what you are talking about, but they see you flying rather than crawling. Your reputation is back.
I have been on both sides of this divide.
3. Building your reputation takes time.
How many times have I fallen into the trap of wanting to impress someone, and therefore hitting them with a lot of intellectual firepower - kind of hosing them. Although it's a truism, it is also true that less is a lot more. Understated competence allows people time to assess the evidence and to make their minds up. After a week or ten days, they may start to trust you and you may acquire a reputation. Attempts to short-circuit the process fatally undermine it. Patience and the Tao!