You're in a market

The best self-employed people that I know have an acute awareness that they operate in a more or less open market.

Contrast this with being an employee where you're essentially operating in a monopoly situation.   If you're the company bookkeeper or the sales representative for the South-West then no one in the world is allowed to do the company books or call on clients in that region except you.

This is such an obvious situation that it goes totally unnoticed until you're self-employed.  The client might promise you all the bookkeeping work or the entire South-Western territory, but only a fool would see this as a permanent arrangement.  Even contracts come up for review from time to time.  Face the fact that you're in a market and accept that markets are devoid of fairness; if the client's daughter-in-law suddenly fancies herself as a bookkeeper then you've most likely lost a client.

In an open market you're really only as good as your brand and when you're self-employed then you are that brand.  This is a shift in thinking if you're used to working for others.

For example, you need to accept that there's no such thing as seniority, only longevity.  Longevity just means that you've been around a while and if you and I are competing for a client then I'll turn your 'longevity' into a negative: you're not hungry for the work, you're complacent and take the client for granted, you're not up to speed on the latest industry trends.

In other words, 'longevity' is just another brand attribute like cheaper, newer, closer, more convenient, smaller, better attention to detail and so on.  

Nb. If when reading this you read the word 'brand' and thought 'logo' then I'd strongly suggest visiting amazon.com and tracking down a few 'Marketing for Beginnners' books.

To succeed in your market you need to understand what your personal brand is all about and you need to nurture it.