First, it is necessary to have very clear the objectives. You can looking for some questionnaire, or studies for to know how it has been measured that you are interested. This activity can help you to identify how you can measure and to investigate the study object.

There are many scales, indicators...about it depend what you want to get, your objectives.

What kind of a questionnaire you need to build up? Questionnaire depends on the population you try to research. there are many conditions based on the study.

Thank you for the answers.tThe subject is about xenophobia.,the questionnaire is for students of secondary school.

What i did before was to do a matrix: objectives-methods-questions. For each objective, i wrote the methods and instruments to be used; then, for each method (questionnaire, interviews, observations, etc.) i planned the questions. for a questionnaire, you might need to put your questions into categories.

Define clear objectives for your survey, identify a sample and look at previous literature in order to understand if something similar has been done and how can you use it (sometimes survey forms are published as Appendix).

Also, try to stay in focus, ask only what's necessary and "prioritize" you questions. Also, keep it simple and use clear questions and don't add description to the questions or to the section (if you can, don't use sections), because this could create bias.

If you have to ask embarrassing questions, use the third person for that, so that it's easier for the participant to answer.

Avoid the use of weights or, if needed, justify them, avoid the description of what you mean with a question.

Insert "test-questions" in order to understand if participants are actually reading your questions, e.g. is this bike beautiful? (scale from 1 to 7) and then "is this bike horrible?".

With regards to the topic of your questions, you should add all the equation that enable you to prove your theory, so you have to cover all the pieces.