There's a saying: to have a friend you need to be a friend. Finding your tribe is thinking about writing not as an art or a craft or as a business (though it's all those things) but as a community of people sharing a love of writing.
Recently on Facebook a young college student declared that the quality of a piece of writing in getting published is unimportant, all that mattered was who you knew.This young man and I shared over 30 friends and since most of my friends are also writers, this pronouncement didn't go unchallenged for long.
Within an hour an editor chimed in to explain how she had gotten her sales by submitting to markets which fit the story she wanted to sell, and as a publisher she does get submissions from people she knows but turns down many if not more than she accepts because the story must first be excellent but also must fit the project she's putting together.She isn't going to damage her reputation by playing favorites.
While many anthologies are by invitation only, there are venues available to those who know about search engines or have gone to the Writer's Market online (or in their public library). And there's always word of mouth from your friends and newsletters from organizations.
Furthermore, while knowing people can be useful, it's not worth much until your writing is up to par. And this comes from being able to tap fellow writers to critique your work.