Mastodon doesn't push people or posts at you. So make sure your profile lists the things you want in common. Work, hobbies, political interests, etc.
Use hashtags, I can't write this often enough as hashtags help you find posts and people and let's them find you.
I never follow back if someone who starts following me has no info in their profile and no original posts.
I search every few weeks on key hashtags to check if people have joined who share my interests.