A data collection form is a way of recording your approach to obtaining the data you need to perform your analysis. Too many people rush out to collect data without creating a formalized approach informed by their data collection plan, thought to the kinds of techniques they will use (like sampling), the categories of data needed, how they will ensure data accuracy and validity, if their measurement systems are adequate, and the necessary effort to obtain the data.
Filling a data collection form forces you to explicitly answer those questions. Recording what kind of data you need and the constraints and required forms the data should take can save you
You also get the benefit of posterity. Later on, when you are presenting or defending your research, you can show the methodical way in which you approached the problem. Or, if you want to further extend or repeat your data collection, you know exactly how and why you obtained your data.
There are many types of data collection forms you could use. Here’s an example: