First you need to clearly identify your research objectives and questions, otherwise don't waste your time, objectives will lead you to variables of your research and questionnaire.

Then, you need to do one or both of the following methods:

1- read previous studies and surveys about practice green (keywords for searching: surveys, food behavior, health, green practice). You will get many good ideas for questions.

1- Exploratory study: make some interviews with some people about what they are interesting about green practice.

it is also will give you some ideas.