Well, this past year I completed 4 rotations at 4 different places and I received pretty good feedback and was told that I would be ranked highly at each and this is with middle of the road scores. So, take this with a grain of salt as it worked for me but maybe not for you. The Anesthesia Secrets book is a great book to read. Other than that:
1. I was proactive, but not in the way. I placed ECG leads, strapped arms down, helped with connecting lines (biz, temp., ECG, TOF, etc.), carted off the bed from the room, etc., all the while STAYING out of the way. I repeated this post-operatively (getting along with nurses that in return speak well of you helps).
2. I developed rapport with the patient and actually knew the patient history. If you really want to impress and feel comfortable, do a preop and ask the doc if they would mind looking at it.
3. Know the basic drugs and when to use them (for example epi vs. neo). Properly label the drugs you draw.
4. Learn to properly mask ventilate the patient all the while maintaining visualization of the chest, appear confident when intubating (you can risk it and try to tape the eyes of the patient, but some attendings just want you to concentrate on the airway). Ask to adjust the table to your proper height. Tell the attending when you see cords. If you don't, back out. Just have a good routine. Intubation and bag ventilation is a simple thing that anyone with practice can get good at, but for some reason students get judged by this ability.
5. Keep an eye out for when the fluid bag is running low and be helpful and ask if they need another. Pretty much try to be helpful; this does not mean intrusive.
6. Learn the quirks of the attendings you are working with.
7. Ask a few questions once in awhile, but don't constantly ask questions in the OR. Sometimes residents/CRNA/AA/Attendings like to relax. It's okay to just shoot the breeze with them.
8. Ask if you can help with anything for setting up for the next case; but make sure you know what that entails. Usually that is drugs (fentanyl, versed, lidocaine, propofol, succs/roc/vec), a couple of tubes, laryngoscope, OG tube, and airways/masks.
9. Stay with the patient and be a fluid part of the team and play nice to EVERYONE including PACU nurses to CRNA's, if you are really bad or really good, you will be talked about, so be the latter.
10. Learn something from one person that is intelligent and use it to cleverly bring up the topic to another person thereby making you look informed which technically you are (ex: "...so during pregnancy a women is more susceptible to chemical pneumonitis due to relaxed sphincter tone, increased abdominal pressure,...and this is why it is preferable to...?").
Finally, show up on time and be appropriately enthusiastic (some people don't like super happy people when they are in the trenches). I hope that helps and I am sure I am forgetting some things.