When sending resume's through email, what is the protocol of following up?

I have sent my resume’ through email to people who have requested it and on a couple of occasions, from people who have not requested it. How do I follow up? Should I wait a couple of days and send a follow up email to make sure they received it? Should I send a paper one through the mail? I’m newly unemployed and had the same job 30 years, so I’m new at this job search stuff.