Sometimes a compliment really goes a long way. To celebrate Compliment Day, simply launch sincere flattery attacks on random people throughout the day, especially those who wouldn't expect it. To give yourself a challenge, find compliments for people that you don't like. The key, of course, is sincerity. Complimentday.com suggests that you try to compliment 2-5 people and provides a list of sample compliments for those who struggle with the art of flattery.