It is a better idea for the freelancers to do the follow up after sending the introductory emails, especially if the freelancers didn't get the replies he desired. A freelancer can wait for a week after sending introductory emails. The resending the emails will make the audience take actions.
However it is always a better idea for an affiliate to use a strong CTA to ensure that audience carry out the actions they want in the first email.
However it is always a better idea for an affiliate to use a strong CTA to ensure that audience carry out the actions they want in the first email.