Data are published and distributed in many ways. Each web site will look different. Knowing some common elements to expect can make the experience less daunting.

• File downloads - of course, there must be data to download. Expect, though, that there may be more than one way to download the data and look around before you to commit to something cumbersome
• Documentation and metadata (or, data about that data - contextual information needed to interpret a set of raw data observations). Data need description in order to interpret it and re-use it with accuracy and validity. Metadata can be of many kinds, but two of the most important are:
  • Study level: information about the study or mechanism that produced the data, including purpose, scope, and primary investigators and funders
  • Variable level: detailed descriptions of every variable in the dataset

Expect to need to use the documentation in order to make sense of the data and expect to have to look for and capture the metadata yourself along with the data files. This means multiple downloads and careful looking on your part. 

1. Brainstorm potential sources and make a plan (considering available time and other scopes)
2. Searching the journal literature - following leads to project sites or repositories of journal replication data like Dryad. 
3. Going to the web sites of government agencies and looking for data web sites, catalogs and repositories
4. Starting in broad repositories like Dryad or DataONE
5. Identifying and looking in disciplinary, regional, or format-specific repositories like Living Atlas and ArcGIS Online
   

• Who produced the data?
• When the data were collected?
• Scope: geography, time period, universe of included/excluded
• Variable names and definitions
• Units of measurement
• How were data collected (e.g., what methods or equipment were used)?
• Are there more data available than what is here? If so, where?
• Look for download options: what formats are available?
• What comes with the download: metadata, definitions, citation?