Know your lines really means knowing and owning your story and being prepared to talk about yourself in a variety of ways. Consider why the employer would want to hire you and what is your added value. Prepare your two minute pitch or overview statement. Interviewing is a business conversation where both parties need to determine if you can do the job, if you are interested in doing the job and if you fit. It is a mutual exploration.
Most candidates get ready for the interviewer's questions, fewer prepare for asking questions.
Ask questions and comment throughout the interview. Your informed comments and inquiry will further demonstrate your interest, show depth, and provide you with better information with which to proceed. Prepare, prioritize and pre-think your questions. Since you can expect to have multiple interviews for any one position, continue to anticipate their questions and what else you want to know. Defer your questions about compensation and benefits until later interviews, preferably when you receive an offer.