Real knowledge is to know the extent of one’s ignorance.

Mapping the boundary of what you know is a real skill, and a rarer one than knowing a great deal. Somebody who can say exactly where their competence stops is safer to work with than somebody who cannot, since the second will keep walking confidently past the edge without noticing. Precision about the limits is what makes the knowledge usable.

In your own field, try drawing that line explicitly. What do you know well, what do you half know, what do you merely hold opinions about. Saying that you do not know a part of it is a professional strength rather than a confession, and people come to trust it quickly.