Researching the Specifics

To complete the research section you simply need to ensure that your product fits it's purpose and also compliments its environment.
You need to consider the function of your product.  An example maybe that if you are designing a piece of furniture you will need to understand the ANTHROPOMETRIC DATA.  If you are designing a storage device then you will need to know the measurements of what is being stored and how many in total.
Remember that the information you collate will inform your specification, and therefore your design will be made at those measurements.  This needs to be accurate because the finished size will need to fit the purpose.