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.

To add more data to the Y axis in a line chart, add additional numbers in cells below your existing data. Right-click the chart, choose "Select Data" and highlight all entries in the single column.

To create a bi-directional mirror bar chart in Excel, you will have to start with the Stacked Bar In the 2-D Bar section. Here are the detailed steps to be followed.

When the relationship between the charted entities is less important than the individual entities, try using these two chart techniques to highlight important details in Microsoft Excel.