That's a good question and the answer is you cannot if:
- they are not interested in searching for someone new,
- use hashtags (and know how to search - topic - country - and so on)
- check who talks to whom
- like to search out of their comfort zone or for example read posts and look at the accounts of those mentioned.
- Like to read everywhere.
A help is if you comment allover the (Steemit) place, who knows someone will think and wonder about what you write.
I am sorry to see no one replied, hereby