The way to learn is by doing. Pick some companies you think are relevant and introduce yourself and keep doing that for as long as you are in business.

A couple of things:

+ "your services" consist of whatever solves the client's problem.

+ don't waste time trying to convince people to hire you. People with real problems don't need convincing. You can spend forever trying to convince someone who doesn't have real problems.

+ consulting is a relationship business. Relationships take years to build. The best potential clients are in established relationships with established consultants. New consultants see a higher percentage of bad potential clients: amateurs and non-payers.

+ selling is hard. Almost everything else is easier.