Some tips I found helpful:
• keep the survey short (like 3-5 questions) if you want volume
• pre-qualify the visitors who can respond to the survey to keep the answers high quality and focused
• prefer to reduce respondents work as much as possible, so multiple choice questions over input text boxes, unless you really want the nuance that comes with a subjective reply
• keep the survey logical in flow. one question leads to the next
• don't ask leading questions, ever (like "Is this product good?" or "Why do you think this is a good product?" instead of asking "What is your opinion of the product?" or "In what scenarios would you use the product?"
for the rest, i co-worked on
this ebook sometime back, would be super useful, with tons of data-backed insights.