Answer:
The employer is really asking, "why should I hire you,?" when they ask, "Tell us about yourself." They don't really want to hear that you're a quick learner, or where you went to school. They want to hear that you are well qualified for the job, get along well with people, require little training, and have a positive attitude. They want to see that you are an honest, optimistic person with integrity. They want to see that you don't plan to come in and "take over."
So, a good answer may be, "I believe I would be a good fit for your company because I am a very positive, people person and I feel I can hit the ground running based on my experience in this industry. My hours are flexible and I'm able to work extra just to get the job done."
An answer like this shows you will not be a burden to the employer by not requiring tons of training; believe me, they're busy enough and don't want to spend too much of their time training you. Also, they want someone who is not high maintenance; someone who is cheerful. This is what I look for when I'm interviewing.