Rouge should always be applied sparingly. Start at the highest point of your cheekbone and powder backwards from there to the hairline (!). Once you have applied a little too much rouge, you can powder the foundation on it afterwards and thus balance the rouge. Sometimes it also looks good if it is lightly applied under the eyebrows and on the forehead.
You can also use your rouge as lip colour. Mix it with a lip balm. This is also good for your lips.