The match process was a stressful time for me for a couple of reasons.
First, as a 3rd year student, I had a difficult time learning about the residency programs out there when scheduling my fourth year. Had I known more, I would have made different externship choices.
Second, as a 4th year student, you wonder how to play your cards right regarding what to tell programs about interest level, etc.
After going through it, I'll give my two cents. I most respect the programs that played by the rules and didn't ask me for a commitment. I found myself wondering what they thought of me, but if you ask for feedback midway through the externship you may get some clues. If you do your best as a student and only apply to programs that you're interested in, and aren't forced to give a ranking, it should work out well in the end for all involved. If you really want a program, tell them. It doesn't mean that you have to tell them they are number one, but let them know how happy you would be there. Go back and visit in December/January to solidify your interest. And for programs that press for a commitment that you know aren't gonna be #1 but that you would be happy at, just let them know that you would be really happy there and that you would appreciate their consideration.
One other tip, I know of several students who ranked only a couple of programs. It worked for many of them, but caspr says that this is one of the biggest reasons students scramble.