What do you mean by revising work?
For the actual exam: once the Unit 3 exam is done, go ask for a spare exam booklet to have a copy of the questions to discuss answers and stuff (or completely not care about Unit 3 anymore and move onto starting Unit 4).
If you meant when you finish all the questions and have time left to check over: I flick through and check if I've done all the questions, then I look over short answer calculations first, double check explanations (usually not much time to alter these, get them right the first time) and then just quickly look over multiple choice. Depending on the time I have left, I'll check over extremely thoroughly (to the point of basically doing the exam twice), or otherwise compromise on depth in most areas if there's only something like 10 minutes left.
If you meant when finishing a practice exam: I look over my answers of course, correct it, figure out what I did wrong, note down if there was a faster way of doing things. I make a list of stuff I did wrong and then go study up on those topics. I add any difficult questions and common mistakes into my log book.
If it's a VCAA exam, as well as doing all of the stuff I mentioned, I look at the assessor report and every question (whether I got it right or wrong) and paying attention to the topic assessed, if they had assessed it that way before, how the state went, note the common mistakes (hoping I didn't fall for one of those common mistakes either).