How can I grow an email list of 100 people to a list of thousands of qualified leads?

If you are looking for a free method then try the following -

Create a contest. Email your list of 100 fans and tell them they will get the following -

Their name in a special acknowledgments page in the book and a 50% off coupon for the price of the book if they share the link to your Amazon book page with one of their social networks.

Set a date for the contest to end maybe 2 weeks out. Whoever has the most shares across all of their social networks in that time frame (FB, Twitter, Instagram, LinkedIn, Blog, etc) will win a character cameo with their name in the book and a free copy of the book.

This would require writing in an ancillary character into a scene in the book that has no significance to the story but is just a way to mention the contest winner's name.

For each share, the contestants just need to email you the share link to prove they made the share.

To build a massive email list, if you play the game that everyone else is playing, you’ll never win.

Create contents. Solve your audience's problems, tell stories that happened to you, and so on.

But most importantly, remember that quality beats quantity.

While everybody is out there pushing shallow contents like “10 Ways to Be More Successful.”

You have the advantage to stand out by creating remarkable material.

Is it hard? Of course, but it’s that kind of strategy that will ask you for more work up front, and will give you disproportionate results once running, like the great Ramit Sethi often teaches.

Once you have your content to stand out, don’t be frazzled.

Instead of chasing tactics, build systems to promote them.

Do you know Gary Vee?

When he was starting out he was spending 20-minutes to create his videos (10%),

and then the rest of the days promoting them, replying tweets, and so on.

Same for Jon Westenberg, very well-known on Medium.

He now has thousands of readers, but once told that he started out by

reaching out to people on Facebook with a personalized and

a not-spammy message, telling them about his new content.

Same for James Altucher, who create and then repurpose his remarkable contents through his blog, Q&A sites, and so on.

He has a system in place for being omnipresent where his audience/target market spends his time.

Choose 1 or 2 tactics to create and promote your contents,

(Guest posting is one of the best when starting out)

Once you have it, stick to them.

Trust the system, and enjoy the progress, remember that slow and steady wins the race.

Email lists can shrink as members opt out of email subscriptions and grow as the business solicits contact information from website visitors. Use varying types of email subscriptions to send more targeted content to specific segments of your marketing personas. Though it might seem counterintuitive to remove folks from your email lists to grow them, emailing only engaged contacts could improve your deliverability and increase the odds of your email getting shared with those outside your current contacts database. Plus, if you are already in a natural email conversation with them, subscribing to more emails can be a natural next step.
You can read more here: https://blog.hubspot.com/blog/tabid/6307/bid/32028/25-clever-ways-to-grow-your-email-marketing-list.aspx
Besides if you do have any questions give me a call: https://clarity.fm/joy-brotonath