If you wish site visitors to contact you through your website then response will be much higher if you employ HTML forms instead of just providing an email address.
The simpler you can make the forms the more likely users are to respond.
Don't ask for any more information than you need. Users will consider lots of questions intrusive and will simply glaze over at the sight of a long form.
Keep mandatory fields to the least you can manage. Users who can't submit the form, until they've supplied information that they may consider irrelevant, just won't bother.
Encourage users by explaining what they will get by submitting their information and provide a privacy statement or a link to one.
Validate user input. Check that the user has submitted the correct information and send them back to the form if they haven't - telling them why.
JavaScript can validate input without the user leaving the page, Ajax can also and is even better, but neither should be a substitute for server side validation.
Make your form forward to a "Thank you for contacting us" page so that users actually know that their information was sent.
Never trust user input. HTML forms are a potential weak point, so make sure that your form script is secure against crackers and spammers.
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