Give a reply

I find a common experience of sending an e-mail to a friend or to a business contact, and do not receive a reply. I know that they had received it, because they reply when a send a reminder or a follow up reminder. They do not reply because they do not know how to respond, or the request was not clear, or do not have the complete information. It is almost like talking to someone, who does not talk back - just kept silent. Is this the right way to respond? What is a better way?