Metadata is structured information describing the characteristics of something; for example, the dates associated with a dataset or the title and author of a book.
Metadata standards provide specific data fields or elements to be used in describing data for a particular use. Some research fields have predefined metadata standards, such as those listed below. Wikipedia also describes and links to other disciplinary metadata standards.
Make a note of all file names and formats associated with the project, how the data is organized, how the data was generated (including any equipment or software used), and information about how the data has been altered or processed.
Include an explanation of codes, abbreviations, or variables used in the data or in the file naming structure.
Keep notes about where you got the data so that you and others can find it.