It would be easy if you could extract your data using one generic form, but unfortunately, every form needs to be customized to reflect your research topic and your key questions.
Here are a few tips for getting started:
Organize your form logically, creating sections for each element in PICO (D), plus bibliographic information.
Create structure in your form, but allow for flexibility to capture variability and any unexpected data.
Build your form and then extract a few studies. Use what you discover to make the form better. Just don’t forget to return to those initial studies when you’ve finalized your form.
It is impossible to design a perfect data extraction form on your first try; form development is often an iterative process. But don’t wait too long to finalize your form. Every time you make a change, you’ll have to go back to the studies you already reviewed and extract new data.