Did you get that second interview?
It's a good sign. You must have been very impressionable on your first BUT now you have to make sure you "close the deal."
The first thing to remember when you are going into a second or third interview is what you stated in the first interview. The interviewer will have notes from the first interview so you need to be ready to follow up on things you said. So that means no lying. If you work hard to impress the interviewer and end up fabricating (a cooler word for lying), you may not be able to recall those lies you told in the first interview. And that usually means no job for you.
Be prepared for questions to ask either about the position and/or the company in general. Search online about the company and get a feel for day-to-day operations. You can ask questions like, “What is a typical day?” or “What is your experience with the company?” This accomplishes two things.
(1): you get to know more about the job.
(2): you build rapport with the interviewer by asking questions about them. It also signals that you are comfortable with the interviewer and builds trust.
Have plenty of SMART questions about the position. Show that you have researched the job and are certain that you are going to get it. You are acting as if you're going to be hired and are just preparing for it. The more inquiries you have about the position the more serious, confident and interested you will seem.
The last thing to remember is to not let your guard down. Remain on your toes and be even more prepared than you were for the first interview. As the interview process progresses you will probably be meeting with the person that will be your direct boss. Interviews with these figures may be much more difficult than the first interview which was probably with a human resource person. Be mindful of this fact and have "ready made" responses for those tough questions like, “What makes you the right candidate for this job?” And don't forget to be creative, you may take some spur of the moment problem solving (Yes, it's usually a test).