Many young people seem to be clueless about making a favorable impression on a job interview.
Being extremely punctual for the scheduled meeting can demonstrate a willingness to always be on time for his/her scheduled shift. Showing up late, even one minute, should throw up a red flag.
A resumé is often presented, and attention to detail and proper spelling are relevant aspects. How the applicant expresses him/her self in the resumé will be judged.
Expressing oneself verbally is also important during the interview. Being engaged in the interview, maintaining good eye contact are necessary aspects.
Some interviewers have been disappointed in an applicant's mode of dress. Many interviews do not require a suit and tie. Nonetheless, a clean and pressed long-sleeve shirt (white is a good choice) and casual dress slacks are always appropriate. Avoid wearing jeans or anything denim.
Some job applicants have either checked their wireless phones or/and texted during their interview. (w0w… if I hire this guy will he always be on the phone or will he be performing his assigned duties?) It seems this issue should be a no-brainer; yet, some job applicants have been guilty of it.
Smart job prospects will have researched the company where they are applying. It will always be smart to mention, at an appropriate time in the process, something like, "I would value the opportunity to be proactive in helping (name of company) fulfill its mission to (give its 'mission statement').
If you feel that you possess the skills to fulfill a job's responsibilities then be confident that you are the right person for the job. Your self-confidence will be obvious during the interview.