Cleaning your dog's ears on a regular basis is an important thing to do, eapecially when you have a dog with floppy ears, because dirt and moisture can become trapped in the ears more easily.
Most veterinarians recommend that you do not use q-tips for cleaning your dogs ears, but i have done this and not had any trouble, as long as you are not getting way down inside of the ear. For the outer parts, it seemed to work okay for me; however, most vets say to use a cotton ball instead.
You can clean your dogs ears with a mixture of white vinegar and water (half and half), and this will dry up any yeast infection they have in their ears. Hydrogen peroxide is another good product to use to clean your dog's ears, since it will usually fizz dirt up to the top where it can be easily wiped out with the cotton ball.