On medicine placement, I was lucky that there was a lot of structured teaching from the consultants within the specialty I was allocated to. I had tutorials based around the core specialties (such as cardiology, gastroenterology, etc), history-taking and also things like reading ECGs and chest x-rays.
Learning on the wards was another story. I was placed on a very busy ward where a number of patients had been there for quite some time with some others who were acute admissions who would probably be in for a week or less. This meant that finding a patient to clerk was never an issue (in most cases, the longer a patient had been in, the more willing they were to talk) and I would definitely recommend that you try and clerk at least one per day. I managed this and it meant towards the end, I was pretty confident when taking a full history from a patient and examining them too.
After clerking, think of the top three differential diagnoses the patient may have (and if they've already told you, think of the other things it could've been that have a similar presentation) and then think up a management plan. Next, look at their drug chart and patient notes to see how close your plan matched their actual one.
Another thing to do is to present these patients you've clerked to doctors and even friends who are medical students. I definitely didn't do this enough (once a week on average for me) and I sorely regret that. Ward round is a great place to present patients and it also means you're less bored than if you just traipsed around aimlessly after the team.
Finally, medicine placement is an excellent time to do some practical skills such as venepuncture and cannulation. Ask the junior doctors what jobs need doing and then ask if you can help them. Attending ward round definitely helps with this; especially if you have a consultant who is super eager to teach.
Unfortunately, I never got the opportunity to see any patients on my own but I did get a few opportunities to do a few consultations while the GP was in the room observing. General practice was a super chilled out placement for me but I learnt a lot. Ask questions - look up anything you don't understand and remember: common things are common! If you can, try and sit in with a variety of GPs - I did a physiotherapist clinic, a few diabetes clinics and saw a variety of conditions in the normal clinics.
My tips for this placement isn't that much different from the ones for medicine placement. Clerking patients on surgery placement is very different as, for example, you have to ask other questions specific to anaesthesia and relevant co-morbidities.
When you go to theatre lists, don't just stand and watch the surgeries. Seek out the anaesthetist on an occasion or two - I did this and learnt a lot about drugs commonly used and also about the monitors used during surgery. Try and find the list the day before so you can look up the procedures and patient's notes.
Finally, be enthusiastic and open-minded! I went into each placement thinking that there was a possibility I might enjoy it enough to consider it as a genuine career move in the future and this meant I asked questions, read up on conditions relevant to the specialties I was allocated to and just kept a log book of each patient clerked and condition seen. Don't go into a placement thinking you'll hate it - you might be surprised! And be respectful to everyone: patients, doctors, nurses, HCAs - remember, medicine is about team work and these people are the ones who will can give you a hard time if you're rude or never on time. A smile goes a long way!
Placement is much better than sitting in lectures all day so make the most of it. After all, once you graduate, you'll never be able to use that brilliant phrase that gets you out of everything ever again: "I'm sorry, I'm only a medical student!".
Just an aside - although I've written this post in reference to third year placements, I am technically in my second year of medical school of the accelerated four-year graduate-entry course, hence why when it comes to OSCEs and formalities, I am a 'third year'.