Arrive early. Anaesthetics has a schedule and a list for the day and they don't like to run behind.
If you are going into theatre you will need to put on scrubs and probably have wipe clean shoes although they will probably have some you can borrow.
If you want to appear keen, ask about the considerations to think about before putting patients through anaesthesia, ask to see patients with the registrar or consultant for the pre-operative assessment. I would remain completely quiet and absolutely not touch anything whilst in theatre, but once the anaesthetist has put the patient under you can ask them which agents/medicines they are using and why, how they work and what are the side effects.
Then think about the experience of the patient. Were they calm, was everything explained to them fully, how did it go, did they suffer any nausea or unpleasant effects?
Write a dairy for every day you are in placement. Reflect on what you saw, learnt and the challenges involved but also again try to view it from the experience of the patient, this is what will be useful in interview later on.
If you have any other questions, ping me. A lot of us have contributed interview questions, start reading through those and building some background knowledge of content from the media, find an area of medical research that you find interesting and read a bit about it from time to time.
Hope this helps
E.