Check these to understand the data

Identify the Challenges – Start by reading the article that we link to. Read about the topic. Write down keywords, definitions, acronyms, anything you can think of about the topic. Literally write it down on paper.
Examine the Metadata – What are the data types? What’s the range of the data in each field and what do those mean? Is the data complete?
Explore the Data – Build lots and lots of charts. Try to gain an understanding of the data. How much variety do the fields have? Is there a data hierarchy? What happens when you compare data across fields? Does one field affect another? What do the metrics mean? How much distribution is there in each metric? How can you aggregate the data?
Remove Unnecessary Fields – Once you’ve explored the data, remove the fields you don’t need. This will help focus you on the data that is important and relevant to the questions you are trying to answer.
Focus on a Subset of the Data – Filter or limit the data to reduce the complexity.
Create a Sketch – You should now have context for what you want to create. Step away from the computer and sketch some charts on sticky notes. These should be very rough sketches. Move them around on a big piece of paper until they form a cohesive message.
Turn the Sketch into Reality – Get back on the computer and recreate what you sketched in your data viz tool. I promise you that sketching first will speed up this process significantly.