This is an unconventional "unit", like MED2000. It runs "throughout" the year and is essentially the bulk of assessment for Year III. The OSCE, unlike pre-clinical ones, is 10 stations (+ 2 rest stations) in a single day, held at clinical sites (not your own) or on campus. The written exam is a 3 hour examination with 100 MCQ and EMQ questions only.
The key to doing well, is consistent practice.
For the OSCE, try and take as many histories and exams as you can, practice in study groups, practice on patients, practice in bedside tutes. Be that guy who sticks up their hand and volunteers to see the patient in the group, you'll get a lot out of it even if it does mean a few minutes in the hot-seat. I'd also recommend, when practicing in groups, to throw a lot of "curve-balls" as stations as this is what Monash likes to do. Make sure you can perform every clinical exam, do every procedure, explain consent for anything, describe pathology specimens, interpret ECGs, etc.
For the written exam, I think there are really two ways to go about this:
1) The "proper" way - consulting textbooks and learning a huge amount of detail. You'll be very well versed in pretty much anything Monash can throw at your but it will take a lot of time and persistence.
2) The "lazy" way - learning how Monash writes exam questions. Get hold of past papers and try and smash them out. Do MCQ/EMQ books, learn what the "buzzwords" are for various conditions. You may struggle if a consultant asks you a detailed question, but you should be alright for the exam.
In the end, I think most people start off with Option 1 and during the tail-end of the year end up falling onto Option 2. Not a bad way to go about it. Either way, finding which way works for you is something you should have discovered in your prep for pre-clinical exams, but make sure you don't fall behind and leave too much to do in the last moment.
To be perfectly honest, the best part of this assessment unit, is finishing it
On to Year IV!