Candidates should dress in a clean, conservative and professional style. Arrive at the interview early to give yourself time to fill out an application and relax a little. When you walk through that door, you need to look sharp. Even if the company is known for casual dress, it is not appropriate for a first interview. You'll have plenty of time to show your flamboyant personality after you get the job.
Candidates often act as though they are the buyer rather than the seller.
Chances are that you will be competing with other qualified individuals for the position. You need to sell yourself with everyone you meet at every level. Be prepared to answer questions regarding past accomplishments, what your strong or weak points are, techniques you have used for solving problems and what you can bring to the company. Whenever possible, quantify the results of your accomplishments with something tangible. Candidates want to share what their objective is before they listen to what their prospective employer's needs are.