Very importantly, if they're being video'ed don't forget the lipgloss
Just make sure that you explain everything you do - don't assume the examiner will give you credit for anything.
In my practice OSCE, we had a CTG to consider, and questions to answer - more like a Viva than an OSCE I suppose. The first bit was to look at the first 20 minutes of the trace and state whether it was reassuring or not. I said that the trace was reassuring, as it had a baseline of 130, variability of 5-10, accels present and no decels., I lost marks because I didn't state the normal ranges - ie, the baseline is 130bpm which is normal as it falls within the normal range of 110-160bpm etc etc. I got a good mark, but I could have got a
great mark.
By the way, it turned out that the trace was someone having an abruption - you had to describe why the second half of the trace was abnormal, what you thought was happening, what you would be doing etc. We had been given a bit of a history - eg, woman arrives on LW with abdo pain etc etc