There is no miracle methods you will gather a profitable following on Facebook.
Always use a professional when posting on any social media.
Keep spam off of your Facebook page from becoming covered with spam. There are some filters that can help you monitor your site all of the time. Any administrator can enter keywords into this tool that will automatically filter it out.
You could create a Facebook group rather than a Facebook page. A Facebook group allows users all interested in a common topic. You could even set up both a group and a page to give updates and interacting.