Excel has a feature to create formatting rules based on conditions of the data you wish to format. This article will show you how to do a couple of the different conditionals.
First, you will need to select the data range you want to format, then select the conditional formatting button on the home tab:
There are many built in options for conditional formatting. If you want to show a color gradient based on values, you would select the color scales option from the above list:
As you can see, it will preview the selection before you actually select it, so you can choose the option that best fits your data.
Another potentially useful formatting option would be the duplicate fill option:
This formatting will have the option to highlight the duplicates, or even the unique values within your data set:
You can choose to change the type of color highlight, or which values you want to highlight by using the drop downs in the dialogue box that comes up. Until you click ok, the formatting will only preview on the selected data set.