Summarize:

Before you show up for an interview or friendly sit down, take some time to pick out a set of attire that fits you well and is appropriate for the occasion. You want to look sharp, but don’t be too casual or make a spectacle of yourself. Remember to comb your hair, brush your teeth and make sure that your clothing is free of dust and wrinkles.  In addition to the obvious, be sure to wear deodorant, clean beneath your fingernails and keep facial hair shaved or trimmed. As the old saying goes, “dress for the job you want.” If you look the part, potential employers will be better able to envision you in the position. Aim for a tone that’s relaxed and friendly yet professional. When you’re not talking, listen attentively without interrupting. The person you’re speaking to should be just as comfortable with you as you are with them. Give detailed answers to the questions you’re asked, but resist the urge to boast or talk about yourself at length.  Do your best not to stutter, mumble or use a lot of filler noises like “um” and “ah.” If you’re asking for a job via email, take care to use proper spelling, punctuation and grammar. Proofread the message carefully before you send it. Just because you don’t get a job offer right away doesn’t mean that you never will. It may be that the specific position hasn’t opened up yet, or that whoever’s in charge needs more time to interview other applicants. Follow up with a phone call or email within a few days to let someone know that you’re still interested and hopeful to hear back.  Confidence speaks volumes. Sometimes, what you lack in direct experience you can make up for in being self-assured.  While determination is a good trait to have, you should learn to take no for an answer. Don’t be too discouraged if you don't get the job—thank the person for their time, then redouble your efforts and make sure you’re prepared for the next opportunity that comes along.
Put some effort into your appearance. Communicate clearly and effectively. Be tenacious.