The PST is a battle against time but the favourable aspect of the test is that it is not negatively marked so it's a no-brainer to attempt every single question.
Bear in mind that it's very easy to get caught up in the moment with a question - you feel like you've invested a lot of time thinking about a particular one and so feel it's worth taking more time again to get it right. It's important to be ruthless. Imagine someone was looking over your shoulder and giving you objective advice about when to move on. Put yourself in that 'mode'. It's too easy to waste time.
Focus on areas where you are naturally good and try to get better. There might be some areas that you are naturally weaker - don't stress too much about these. Get yourself to a level where you feel competent. It's difficult to be top notch in all areas but easier to be fantastic in one and fine in another. There is only so much practice you can do and so it’s more about developing a strategy to ensure you don't lose against time.