Persistence is only half of the art of the follow up — the content of your message has to be on point. Use these email templates from Dave Kurlan and others. Source: 9 Sales Follow-Up Emails the Pros Use to Engage Prospects [Free Email Templates]
The 5 key steps on how to write a follow up email that actually accomplishes your end goal, including tools and email templates to improve your follow up. Source: 16 Templates For The Sales Follow Up Email