Imposter syndrome is a devilish beast, that's for sure.
When we don't know what we are going, or more to the point doubt that we know what we are doing it can be a terrible terrible thing.
The first thing to do is recognise when it exists.
The next thing to do is to figure out why it's happening, for example are you struggling with a tough problem.. such as what am I doing, what are we doing, what is the process to use etc etc
And then plan out the solution for example if imposter syndrome "kicks - in" during a first meeting with a client then define the process that you need to use with that new client. Even if it feels like there is no process with that client... underneath I'm sure if you step back just a little bit and think about it you will find there is a simple process. Obviously this helps if you have worked through closing a few clients but yes there is a process.
In short the answer is to find, and I mean find, not build artificially structure and in doing so you aren't swimming endlessly in a horizonless lake you know where you are, you know what you are doing and you know what you're trying to achieve. And knowing the answer to that gives you the sort of clarity that you have navigating the streets of New York as you move up from 33nd to 34th street and so on. It's that simple.
So I repeat the solution is structure.
Unfortunately if you haven't as yet got many runs on the board getting new clients then it is nerve wracking but being aware of the insanity that is imposter syndrome and thinking about the happy clients you do have / past achievements in life etc etc do help to calm the mind. Talking through the objectives of any situation in a logical fashion also help a lot too.