For example, you could show line graphs for temperature and humidity on top of each other. For this purpose, Excel lets you add a series of data to a chart and plot it on a second y-axis.

How to Plot Two Things on the Same Y Axis in Excel. Properly formatted charts and graphs can help you grasp the patterns and trends hidden within the raw data of an Excel spreadsheet.

It's easy to turn an Excel chart into a visually compelling object. Susan Harkins walks through the steps for jazzing up data points with a simple formatting trick.