During your interview make sure to ask questions.  These can be about the job at hand, etc.  But don’t phrase the questions as demands.

If you are interviewing for a job then research the company first.  Know what you can about the history, structure and mission and point out places where there is synergy between you and the company.

Always have a copy of your resume with you.  Some interviewers ask for it just to test you…

Make sure to keep eye contact with whomever you are interviewing with.

If you’re asked technical questions and you don’t know the answer then it’s OK to say that, but follow it up with where you would look for the answer…

Interviewing is never easy.  But it can be a lot harder if you try to take control of the interview.  Let your interviewer drive the agenda.  Let them set the pace for the interview.  And most of all, let them figure out what it is they need to know about you.

Race, religion, sexual preference, family makeup and other items that are illegal to discriminate on just shouldn’t come up in an interview.  It is illegal for the interviewer to ask questions about it and (to me at least) it is unprofessional to bring up.  Can you do the job?  Are you the best candidate for the job?  Why?  That’s what matters.  The rest of it is irrelevant to the job and should not be discussed in any way, shape or form.

Cocky is bad.  Be assertive and confident but there is a line.  Be careful not to step over it.