Everything everyone said above basically.
After being on the other side, it becomes pretty stark what really matters and what doesn't. The decision amongst candidates is hard when you look at it strictly on paper but pretty apparent when you get to see them inside the department. I will however add these things which are in no particular order that I feel are important personally.
1. the 2AM or 4AM litmus test. Are you someone that I would want to have working with me at around 4 AM when feces are hitting the fan? AKA. Can I see myself working with (and wanting to work with) you for the next four years?
2. Are you teachable? Which then leads to, can you put two in two together with some gentle prodding and be able to connect the dots in the future. If you've listened to some podcast or some journal, bring it up when we're not slammed and it could be something fun for us as residents to learn about too or try if the attending is down for it. We like to try new things too
3. Do you follow up with your patients? - I feel like auditioning students lose sight of this or do not feel that this is important. Often they feel that it is the best showcase of their "skill" to see as many patients as possible, wait impatiently behind while resident/attending is furiously charting away to do their brief presentation and run off to the next room. Please pick up 2-4 patients (max 4) and follow up with them. Ie. if we gave zofran/pain medicine/gi cocktail/headache cocktail or whatever, follow up with them quickly after and reassess to see if they're feeling better and let me/whoever know. Also follow labs and imaging. We do run the board often but if you know an abnormal lab value or results of imaging is back and there is something that needs to be done ie. dispo/replete lytes/call consultant, let us know.
4. Make our lives easier. We're a team, whether you envision it that way or not as a student. The attending, me (resident), intern and you. Our mission of the day is to treat the patients in the department so if you can make our lives easier, you can bet we will be remembering you. This goes from pelvics to lac repairs to listening to the EMS give their report on the latest pt that they rolled in to following up on patients that you picked up on their labs and reassessment after treatment to bringing the sad mom a tissue to getting that patient the warm blanket they always wanted to helping to log roll a patient off a backboard to getting the bedside US for the cardiac arrest coming in etc etc. You may think these things are trivial. I don't.
Icing on the cake: know your dispo or what you think needs to be done and tell me why. This is something I think needs to be fleshed out during residency but have an idea of is this guy going home or is he staying. Back yourself up with TIMI/HEART score/PERC/PECARN/new orleans CT or whatever 13135971357 other score.