It is my opinion that a company will offer you a position if they feel you are the most qualified, interested and available candidate. Throughout the interview and at the wrap-up you should consistently reinforce that you are
qualified (can do), interested (want to) and available for this position. Be rehearsed and have your qualifications ready (technical competencies and experience, systems knowledge, industry knowledge and your interpersonal strengths). Your interest should be evidenced by interest in the job content, chemistry and career path you see at the new company.
PREPARE!
You most probably will not be the only qualified candidate considered. The deciding factors will be the way you present your skills and qualifications relevant to the position, how you conduct yourself during the interview, the image you project and the ‘chemistry’ you have with the hiring manager(s) and current team.
Understand the purpose of the interview. Most employers base hiring decisions on subjective information. Your past experience is usually a good predictor of your future success. It is up to you to help them understand what you have accomplished, how you have done it, and why you have made the choices you have. Rehearse your material in advance. Think of everything you have done that is related to the job you are seeking. Explain the challenges you have met successfully. Begin by explaining the problem, what steps you took to solve it, and the results. Time your responses to make sure they are not too long.
Stay away from any negative aspect of the industry or previous jobs. Know your skeletons and move on. Try to communicate the negative situation in a clear, short and concise manner. Also, be careful so as not to sound like a complainer about previous companies and bosses.
Review your resume thoroughly. Be able to talk about your experience without looking. Bring 3-5 copies of your resume. One for yourself, one for each person on the schedule and 1-2 extras. Though they should have copies it is good to be prepared. Bring to light any significant accomplishments or letters of recommendation.
Take a daily planner/portfolio along. In the planner, write your technical or job related questions. This makes them available to you. Also have it available to take notes. If there are questions that occur during the interview you would like to discuss, jot them down.