Disclose what you will do with the sender’s personal information

People don’t like giving away information, because who knows what’ll happen with it.

That’s why it’s important that you substantiate every bit of information you ask for. Say why you need it, and perhaps more importantly, what you won’t do with it. 

Need an email address? “We will not give your email address to anyone and will not use it to send you marketing emails.” Need the sender’s country? “We ask for your country so we can offer you specialized support for your region.”

The rule of asking for as little as possible still applies, but whatever you do ask for, explain why you’re asking for it.