Make it Easy for People to Respond
Whenever possible, distribute questionnaire at the end of a meeting or discussion. If that's not possible, assemble a group and have them fill out your questionnaire on the spot-at an evening coffee for parents with children in day-care, for instance. Facing them, you can explain the purpose of your research and invite questions, the answers to which will instill confidence and build interest.
If you must mail your questionnaire, include a concise letter explaining your purpose and what use you will make of the replies along with a self-addressed, stamped envelope. You might also indicate how much time will be required: no more than ten minutes, for instance, or some estimate identifying the task as reasonable and easy.
Professional pollsters often offer a small inducement, a morsel of bait to increase the rate of response: a small check or a coupon good for a free jar of pickles. You might promise a copy of your finished document, a brief report of the results, or a listing of each respondent's name in an acknowledgment.
Even with such inducements, professionals find a response rate of fifty percent or higher difficult, if not impossible, to achieve. That is why they often conduct surveys by telephone, with the caller filling in the questionnaire for the respondent. You might also use this technique, but better results will come if you distribute your questionnaire in person.