A questionnaire should have a clear consistent layout, leave adequate space to answer, bear a large font size and appropriate page breaks. Experimental layouts, fancy logos and disturbing features such as "printed on recycled paper/is an equal opportunity employer" should be avoided. In some cases, using colour or printing the questionnaire on coloured paper may help to increase the response. This depends again on the targeted audience and should be discreet and tasteful.
Filter questions may be of use if some questions or a group of questions are targeted to a subgroup of the respondents. This will enable interviewers a smooth flow through the questionnaire and shorten the time to fill in the questionnaire in self-administrated questionnaires. Similarly, it is important to give clear instructions to interviewers or respondents. This will reduce misunderstandings.
Closed questions on a paper questionnaire can be pre-coded. This means that a number is assigned in advance to each possible answer . Coding will enable a quicker and easier data entry. The ideal code numbers depend on the software which will be used for data analysis. Some software packages only accept 0/1 codes for dichotomous variables. In order to avoid time-consuming data cleaning, be careful to choose appropriate and consistent codes for all variables in advance.