How do you launch a market with zero users?

I'm in the early stages of starting a website whose main feature is a marketplace for a specific service. In order for this website to be successful useful it requires users on the sides of the market (clients and service providers).

What are some good strategies to have a successful launch? The website obviously doesn't need hundreds of users on day 0, but in order for it to be useful for either party there needs to be at least a handful of users on both sides of the market.

For context: the service provided is a skilled trade and the service can only be done if there is material provided by clients. It's similar to picture framing in a sense.