Show enthusiasm for the job while relating your answer back to specific job requirements.
Well, I bring nearly 10 years of customer service experience to the team, I really enjoy helping others, and I've also completed advanced certification courses. The combination of my work experience and knowledge make me confident that I'll be a really good fit for this role.
Don't badmouth other candidates, but explain what you think sets you apart.
I stand out from other candidates because I share your organization's passion for renewable energy, and I have the educational background to back it up. I graduated from a very good engineering program, where I concentrated on energy consumption. In fact, for my senior project, I helped build and install air panels for low-income families. I'm excited about the future of solar technology, and I'm confident I can make an immediate contribution to the team.