I have given you guys some creative questions to ask while in an interview and an idea of what to expect. Now, I'm going to go over things you must do during an interview. Think of it like a routine, if you miss a step you are thrown off and it is usually a bad thing!

1. Have extra copies of your resume handy
Many of the people who interview you will have printed out a copy of your resume, but there are times when the interviewer asks if you have one. You never want to be the interviewee that says, "No, I don't. Sorry." That makes you look unprepared and unprofessional. Your goal is to look prepared and show them they should hire you over the other candidates. 
2. Smile and come off friendly
No one wants to work with someone who is uptight and uncomfortable. Yes, it is okay to be nervous in an interview and the interviewer will understand, but you have to at try and connect on a personal level. For example, I bonded with one of my interviewers over being a makeup minimalist. People want to work with those they can connect with so coming off friendly and eager is good. There is a fine line between trying too hard and not trying enough so try to be yourself as much as possible, or the more open version if you are shy.
3. Speak clearly and confidently 
Most job positions require your to have communication skills, the ability to speak to others and get your message across. Not everyone is a great speaker and that is okay but be sure to not overuse the word like or use to many fillers like "um, er, uh." Speak moderately slow, enunciate each word properly, and speak in a moderate volume so you can be heard.