Constructing the right match list begins with taking advantage of the interview day. Truly, the most important part of that day is to get a sense of the program. The "je ne sais quoi" of the program (justifiably or not) will turn out to be a huge factor in making up your rank list. It is difficult to pinpoint exactly what you did and didn't like about each place you visited, but your overall impression is extremely meaningful and can give you a sense of whether you would fit in. Keep in mind, however, that one day is not always an accurate representation of a program. Strongly consider revisiting programs to get a better sense of the department. In fact, the revisit is a tremendously useful way to let a program know your level of interest.
When making your list, it is vital to know how the match works. For good descriptions of the matching algorithm follow these links: (1)AUA Match Explanation (2) NRMP Match Explanation (same algorithm as the AUA match). The most common mistake that people make about the match process is thinking that if they rank a less-desirable, but more attainable, program higher on their rank list, they will increase their chances of matching there. This is false! Go through the examples on the NRMP site and make sure that you grasp the nuances--you have spent innumerable years in school trying to understand things that are completely irrelevant, so spend 10 minutes understanding the match! Remember, ignore how you feel the programs will rank you, and rank the programs based on your desire to match with them!!!
In general, there are countless approaches to actually making up your match list, but most people fall into one of two camps: 1) Make a big list of qualities you are looking for and rate each program accordingly (see MyAgenda module of this site), or 2) Go with the general impression you get of each program. Each method has its own merits, and, most likely, you already know which one suits your style. No matter which approach you take, you will find yourself, in the end, going largely with your gut instincts. You may be surprised to see how many factors other than the quality and reputation of the program play into your decision. You will be signing on for a rigorous five or six years, and you need to try and place yourself in a position in which you will look forward to going to work. As far as concrete advice goes, here are some suggestions:
You will submit your match list online to the AUA before an early January deadline. You should receive an email confirmation after you submit your list. Obviously, try to submit your list well in advance of the deadline, so you can relax after you get your email confirmation. After you submit your list, you can change it for any reason by calling the Match line at 866-746-4282 (x3913) before the actual deadline.