The following steps can help highlight cells that are above or below a target value in Excel:

1. Select the cells where you want to highlight values
2. Go to Home > Conditional Formatting > Highlight Cell Rules > Greater Than > Enter the value to highlight
3. Choose the background color from the drop down > Press OK
4. Go to Home > Conditional Formatting > Highlight Cell Rules > Less Than > Enter the value to highlight
5. Choose the background color from the drop down > Press OK