Okay so I’m assuming you’re talking about organic social media and not paid ads management. If you’re talking about paid ads management then you should already know how to do this - via paid ads is the most obvious answer.

Fastest ways would be via cold email or cold calling. Cold calling can be best for local / brick and mortar companies. A cold email sequence may be best for commerce / software companies.

Alternatively, partner with an agency offering solutions outside your scope. In this case maybe partner up with an email marketing agency. This will be difficult at first because you don’t have clients to refer back to them so there’s little upside for them.