On an interview, remember the point. Your goal is to explain how you will help the company if they hire you. How much you need the job is irrelevant. You are a resource (not a job beggar).
The key is to focus on your selling points? They want to hear about how you will meet their needs and solve whatever problem is making them look for someone like you.
The first thing you should do is go over everything you know about the company and the person you will be meeting with. Read over every email you got from them. Reread the job posting. Read their web site. Read their LinkedIn page.
As you are going over these things, ask these questions. What do they need? What do they want? What can you do for them? Be prepared with answers to these questions before the interview.
Then make a list of the points you want to make during the interview. These points will be a combination of the things you found in your research, and the things that you feel are your particular strenths. Then in the interview, as you have the opportunity, you can address each one. I actually bring a summarized bullet list into the interview with me to make sure I don't forget anything (I don't read off the list, I just have it to check during breaks etc.)
After you have your selling points ready, prepare some stories. To get my current job, I deduced that teamwork was very important to the hiring manager, and the company culture. Fortunately teamwork is a strength of mine. Of course, just saying this is meaningless. Rather, I had specific stories of when I worked closely on the team. I was prepared to give details. I was prepared to explain results. And, since I had done my homework, I could talk with passion about real stories.
Your stories can be about coursework. The can be about work on film (for example to talk about creativity).
Stories are a great way to present the best parts of yourself in a real way.
Understand their needs. Present yourself as a resource. Provide evidence in the form of real stories. That's the best advice I can give.