Confidence translates to higher success- how to help?

In the summer we do advising for incoming first year students. All students coming to me have declared the same major. I had three students this week to advise. They pretty much all take the same courses, with the exception of which level of Freshman English they take.

One had a B average, and ok standardized test scores. She came late, but once we got started, and chose her classes she seemed excited about coming to college. She was unsure about exactly where she wanted to take her degree, but seemed relatively confident.

Student two's parents come in with her, both looked me in the eye, gave me a firm handshake and then disappeared (a good sign, the disappearance). She had a very high B average, great tests and had a 5 (the max) on an AP exam. She seemed a bit bored with the class-choosing process, and took it all in stride, as if this were nothing out of the ordinary.

Student three came in timidly with eyes down. Without knowing her stats, four years of Freshman enrollment gave me the hunch (bias?) that her numbers were lower. Upon looking at her file, this was confirmed in this instance.

My preconceived notions are forming such that students - before they even arrive at college- have a feeling of whether they can succeed or not. Often that confidence or lack thereof work together with other factors to produce success or non-success. What can I do to bolster student's confidence realistically in order to set them on track for success? I don't know yet, but here's an example of what I am doing (right or wrong) currently.

Student three was local and planned to commute from home... not to live on campus. Studies (of which I can't remember the source at this moment, apologies) show that 40% of students that don't live on campus their first year don't complete their degree in 4 years, higher than those that do live on campus, all other factors considered. After helping this student choose what seemed like a good schedule, and conveying hopefulness about her schedule, I mentioned that as a commuter student she had a special challenge that simply needed her attention and intentionality.

I told her about the study, and suggested that she try to stay on campus longer than just for her classes, that she get involved in activities, and that she dive right into campus life the best she could.

Did I say those things to the students with the high scores or the confidence? No. But that's not a fair comparison, because they aren't commuting. Did I end up helping confirm to her that success is for other people? God, I hope not, but not knowing her I could have! Did I try to forestall right up front a potential pitfall she may encounter? That was my hope, at least.

I need to speak to each student differently depending on their scores to determine their courses. For example, to someone who gets a 5 on an AP math exam, I don't say, "How's your math?". I just suggest calculus. Students whose quantitative scores are low on standardized exams I DO ask that question to see how they are feeling about themselves, something that will help me determine whether to put them in quantitative courses right away or put them off. Am I subtly confirming a student's fears by speaking to them in that manner? Am I transmitting a bias? I really hope not, but have not found a better way.

I know that as an advisor I will say something that will stick in a students craw and will stay with them forever, probably never remembering the incident myself. I would like to minimize these instances or, turn them on their head. I remember a session with my advisor after a sophomore slump when he said, "You'll never get into grad school with these grades" (actually they weren't THAT bed). And my reaction was, "Jerk. I'll show you". I *didn't* say, "maybe you're right, I'll opt for something else" (when the evidence shows that I COULD do it). If, when advising, I say something similar (and I will, just by accident) I would love the student to have the former reaction and not the latter.