What the interviewer wants to know is how well you know yourself and your strengths. They also want to see that you have been able to pick out the strengths that are relevant to the job in question.
What They Don't Want To Hear
They don't want to hear typical clichés or phrases without an example to back what you are saying. They also don't want to hear about any strengths that are completely irrelevant to this job.
What They Do Want To Hear
They do want to see that you have actually sat down and thought about the strengths most relevant to the job in question. You could sit down and highlight the strengths needed for the job states in the job description. Be sure to also give them very specific examples of how you have used your strengths for your former employer.
Good Luck!
