The quality and validity of your visualization project hinges on collecting good data. You will likely collect data from existing sources and prepare methods of collecting your own data. You will be planning your data collection in parallel with prototyping your team's dashboard. They will co-evolve.
Download Currently Available Data Locate freely available data that you will (or may) use for your project and download a copy. If it is CSV data, import the data into a spreadsheet and verify the columns are correct. Place any files in your group's online folder.
Create Survey(s) for Custom Data Collection If your team needs to collect some of its own data you can create an online survey or ask in person. Either way you will want to create a Google form (or similar) to record results, since responses can automatically generate a spreadsheet of data. Once you create any surveys, test them to ensure that the responses generate the data that you expect. Keep a copy of surveys in your group's folder
Optionally, Prepare a Request for Data If you would like to request non-public data from a source that you believe has valuable information, prepare your request and how you will deliver that request. This could be by email, personal request, letter, or other social media. Keep a copy of the text in your group's folder.
Evaluate your Survey(s) with Another Team Once any surveys are created, conduct a dry-run with another team. You can do this whether it is intended to be an online survey or interview.
Be prepared to share with your class your data collection plan and be sure to document each items as described above.