Well I'll give you some insight on my experience. I landed 2 very solid (as per my interviewers, never got to see them) LoRs from a month's experience at NYP-Cornell (actually did 2mos, but the people on the other month were in another speciality and were late with the letters).
Now more than half of the following will be obvious and known to you, albeit very useful:
Before the rotation:
0) Now I know you're going for gen surg, which greatly differs from my choice, but when choosing the specific rotation (eg, floors, ICU, outpt) think two things:
-Where am I stronger? if you do better at one than the other, choose it. you're not there to learn as much as you are to stand out!
-Where am I bound to get more one on one time w/attendings? I chose outpt because I enjoy it, but it also provided me with tonnes of time to speak and do things in a laid back fashion. I wasl also in L&D in obgyn and this was much more intense, but unproductive due to the high turnover of on-call attendings, the heaps of work and, to my opinion, the use of masks, caps (I think visual memory is very valuable!)
During the rotation:
1)be seriously proactive from day one. Stand out, behave like an intern and not a student. we pretty much do much of the patient management down here so we're used to being hands on, opinionated, etc... There's a patient to be seen? step up before you're asked to see him/her.
2)That is, of course, to an extent. don't controvert unless the point is solid and well laid out- no one wants someone to come and impose views. Learn from them, but be sure you also have stuff to teach them. we conferred 90% of the patients with staff and residents and it was always a good time to give some input, even if it isn't the final decision.
3) Ask, ask, ask. not dumb questions (yes there are dumb questions) but remember there are no dumb questions (wtf?). Don't let silence take over while with your sponsors...even relatively obvious questions (eg., "would x be better than y in this patient?...") so long as you can word out some reasoning and start a small discussion ("...because he/she has z comorbidity and it is possible that x...."). I did this so often I thought it was dumb, and yet more than half the times fellows and other attendings would chime in.
4) you don't have to know everything but much as in point 3, a guess with a solid reasoning will spark conversation rather than a blank stare. communication always earns points!
5) if you master another language and you plan to go to a major hospital such as MGH, use this to your advantage. I'm fluent in spanish and french (and fairly good in dutch and german) which for a major hospital (ie, hub for foreign visitors or underserved populations) was quite useful. I took on patients as a translator more than as the in-charge guy half the times, and this made me fairly well-liked with the residents and fellows when they needed any translation (an on-the-phone translator will never equal the flow of communication).
6) play your foreign cards. Bring new stuff to the table. I am doing peds and am a big fan of the IMCI initiative in place in developing countries, but rather unknown in the US. so this was a healthy set of ideas that was also good for discussion. Whenever some random disease or treatment comes up, if (again) you have the reasoning to back your point, comment on how they'd do things in your country. beware, though- don't do it as though they're doing it wrong- it's a tricky card to play, and you want discussion, not controversy.
7) a big, final DURING- I never once mentioned I wanted LoRs. now this is very personal, some people say upfront, but in my opinion, that'll only make them more critical of your performance and not in a good way. Let your overall performance be the judge of thingsI was offered one at the end of the rotation and even left the subject there for the moment (read below).
After the rotation
8) Stay in touch. if you had a good rapport, you'll get their emails. Email in a few days to say thank you; ever so often, let them know what you're up to- I told my LoR writers about my studying for the steps, then the scores, then the next step etc etc. Even told them when I was going back to NYC so I could drop by and say hi- got invited to lunch by them. I dropped the LoR request then and there, one full year after being with them.
9) be polite if you're in town....spare a minute to drop by and say hi.
10) also keep in touch with residents and fellows if you can- sometimes they interview, or get a word in for ya.
11) and be polite even if things are hopeless. I was basically told they wouldn't interview me at the hospital months before but that didn't refrain them from wishing me the best of luck. And by the description I got on my LoRs (I didn't see them, and didn't bother asking to do so either) from interviewers, they were themselves sincerely hoping to see me there. Then again, they're two of the sweetest people I've met, so I'm glad to have kept a long term friendship going, without the pressure of being on their residency program. In the end, I landed one of the best programs so one door closed and a bigger one opened!
Hope it all helps