Dress in the nicest clothes you have. It is possible to overdress for a job interview, but this is infinitely better than underdressing. I recommend a shirt, tie and sports coat.

Avoid the usual stammerings of everyday people, such as 'um', 'like', and 'you know?'. Look at your interviewer in some capacity the whole time. Dont be robotic, just try to be natural, yet formal.

Just let them know you really want the job and why you want it.

pretty much nailed it. Dont be a tool. I like to lean back and cross a leg over and just be kind of stone faced ish like im interviewing them. Because I am. I wont work for a tool. Make that clear. Express the things youve learned from your other jobs and how you think theyll help that company out. Dont talk about how you want to get a job. They know that. and dont want to help you. Your mission is to explain how you are helpful to them.

break the ice with a gay joke.