You respond to journalist requests on topics related to your niche, say you have a website about dentists/teeth/oral care and you've got a dentist as your contributor/author, you can answer queries from journalists on such subject matters. Journalist might ask for a quote on the best way to mitigate a tooth pain when you're not close to a dentist/healthcare facility/pharmacy. Your dentist would then quote something like "close oil is great to prevent further toothache, albeit only temporarily"
The idea is that it would be quoted in the article along the lines of
Dr Dent Ist, of Randyseoppc Dental Care, said that "clove oil is great to prevent further toothache(s), albeit only temporarily"
The same idea happens in forums, but you need to have aged accounts, need to know the forums, so that they don't delete your links and so forth. I recommend
@el_cucuy