Social Media Influencer
Or you can instead focus on growing your own social media accounts. And if you garner enough influence within your network, you can build a business as an influencer that works with brands to promote products and services on your account.
You can also offer a more specialized type of service like SEO for businesses that want to improve the chances of their websites showing up in search results.
Social Media Consultant
Alternatively, you can simply offer your social media expertise to clients online instead of actually managing the accounts for them.