A simple way of having more respondents is to invite them from your website or blog. To do so, you only have to select "From a website". You then only have to copy/paste the text within the text-area and specify the link type:
Full page : The link will open a new full webpage.
Big pop-up : The link will open a XXX x XXX pixels window.
Medium pop-up : The link will open a XXX x XXX pixels window.
Small pop-up : The link will open a XXX x XXX pixels window.

NB: For the qualitative questionnaire, the publication of the URL from your website works a little bit differently. As a matter of fact, remember that the qualitative questionnaire requires a login and a password (so that the respondents can come back to their resonses, complete them or modify them). The link that you give here leads therefore to a generic Sharing-Data page that ask the respondent to give his login and password. He will need to register in order to get this information if he not yet a regular Sharing-Data use.
For the quantitative questions, the choice of the language is an important parameter. If you select "All languages", the link will lead to a generic page asking the respondent to choose amongst the different language available for your questionnaire before accessing it.