The best marketing for a writer is their own writing, showcased at an ad-free website kept current by frequent blogging. I don’t see any value in Twitter, Instagram, or Facebook. Maybe a LinkedIn presence if you want a social media feed.
Time spent pursuing more followers on social is misdirected. What’s the hope? That your tweet on the Canadian bobsled team lands you a job? Good luck.
A better proposition is to spend time directly targeting employers with queries instead of hoping chance will bring them to you. Keep sending out article suggestions, book proposals and job applications.
Developing more followers seems a waste of time. Whether you have one hundred or one thousand followers makes little difference to a harried editor who looks at two hundred article proposals a year, only to accept twenty that meet her editorial requirements and which captures her imagination.
Time and chance happens to us all. Your query on the frogs of Borneo might elicit a spirited reply from an editor who just visited Southeast Asia, or stony silence from an editor who despises the slimy things. In either case, you have to research a publication, draft a winning query letter, and solider on past disappointment.
I understand with books that there may be a difference. Increasingly, editors want you to bring an audience to them. More followers could help. But what kind of time will this take from working on your writing? Ideally, your website writing would reflect on the book you have in mind. Let me go off on a tangent.
I get the most likes on this blog when I write about poetry. Should I, therefore, write more about verse than prose? I am not a poet but I can see why people tailor their sites to their statistics. Your call. But you may wind up far from your calling.
It may be better to forget likes and followers and continue to work toward what counts: satisfying yourself and meeting the needs of an editor. Note that I did not say pleasing the reader. Your editor comes first. After your query is accepted, then comes the reader, following the editor’s guidelines.
As to how the editor gets to know your work, that is for your query letter and your online portfolio. As to Twitter, Facebook, and Instagram, I see them as time bandits and no substitute for a comprehensive writing website.