When you are discussing numbers, graphs and tables are a great tool. Both can be ways to give readers a sense of the numbers and the relationships quickly. Complicated data can become simple to interpret when it is well organised in tables and graphs. So how do you make sure your graphs and tables are well organised? You need to balance having enough information in them so they are completely and easily interpretable with keeping them as simple and uncluttered as possible. It will take some creativity to get this balance right.
This article from the Vanderbilt University Assessment Website has some key points and good examples to follow.