We've been consulting the Retro Nerd Girl movie review channel for the past year. It took a year to get her first 100 subscribers, without any social influence whatsoever.
When we first began working with her she had 32 subscribers in March 2017, with about 22 low viewed videos on her channel.
She had a few things working for her from the start like great branding, great content that need a few tweaks to be more shareable, and a good number of videos to increase her validity.
Here are a few things she did to get 100 subscribers in June 2017:
We encouraged her to create a twitter account. We asked her to follow similar twitter accounts, post once a day and post a combination of information about the channel and links to videos, especially the new ones.
Then we asked her engage on YouTube more often. She posted a teaser video for her main videos to keep subscribers interested and newcomers aware of her activity on the channel. She left comments on other videos and she optimized her video tags and description to reflect what was in the video so she could rank in searches better.
Good luck Retro Nerd Girl and congrats on 100 subs. We'll be keeping in touch!