The first thing to remember when giving any medication is to be calm and not communicate anxiety or nervousness to your dog. Have all the materials ready before calling him over. An assistant, if available, sometimes makes the task easier.
Look into your dog's ear to determine the entrance to the ear canal. Since many dogs have numerous cartilage folds in their ears, these external folds can often easily be mistaken for the ear canal.
Immobilize the head by gripping the dog muzzle firmly. Drip the medication into the ear and don't let the head go if you don't want the liquid splattered all over the place! Dogs will normally shake their heads furiously when they feel liquid running down the inside of their ears.
Once the liquid has run down into the ear canal, gently massage the outer ear for a minute or two to help the medication be absorbed.