I have two handy ways I use conditional formats:
1. In a user form, you can highlight a field that require input by setting up a condition to turn it yellow if the cell is blank. Then, when the user enters some data, the cells turns white again.
2. You can also use conditional formatting to hide those ugly error messages (#NA, #NAME?, #DIV etc). This is perfect when such errors are unavoidable, but you don't want them to clutter up your worksheet. Just set up a format to change the text color to white whenever the cell formula is "=ISERROR(A4)", where A4 is the cell reference.
