You'll notice that the word "dollars" is already written on your check - so you don't need to write it again.
Write the "cents" portion using a fraction. For example, if your payment is for $8.15, you'd write "Eight and 15/100". If your payment was for $8.95, you'd write "Eight and 95/100".
Immediately after you read out the amount, you should draw a line all the way over to the word "DOLLARS". This makes it harder for anybody to write something else in that space.
Do You Even Need to Write Checks?