Ask an experienced professional what they offer and the answer usually arrives as a biography: years, titles, sectors. That is a correct answer to "who are you". It is not an answer to "what will you change for me".
Customers do not buy years of experience. They buy a specific outcome to a problem they already recognise. So the first conversion required is from biography language to problem-and-outcome language.
A simple working test: write one sentence in this shape, without mentioning your years of experience. "I help [a specific group of customers] achieve [an observable outcome] when [a particular situation or stage]." If you cannot fill the blanks precisely, the gap is not in your expertise. It is in the definition of the customer and the outcome.
The first blank is usually the hardest. "Companies" is not a group. "The private sector" is not a group. A useful group is one where you can name three real people you know are facing the problem now.
The second blank reveals whether the outcome is observable. "Improved performance" is not observable. "Shorter monthly close" is observable, and the customer can value it without your help.
Once the sentence holds together, one step remains: testing it. A sentence on paper is not evidence of demand. Evidence comes from conversations with people in that same group, where you hear them describe the problem in their words rather than yours.