I think the best is to work as fast as possible. Preferably try and finish Q1-5 in less than an hour. So you can spend the next hour or so to have a good attempt at question 6 and 7.
That's pretty much it in a nutshell. To get through the first 5 questions by about the hour mark though requires excellent proficiency at the basics. Practice just the first five questions from the last decade's worth of papers and see how long they take you. All these questions will be pretty routine and after repeated attempts at this process, you should find yourself speeding up and recognising the short cuts available to you if you know your stuff. Just make sure that if the questions ask you to "show", that you provide enough evidence according to the marks worth of the question.
Question 7 and question 6 upon occasion are a different kettle of fish. These usually require some application of knowledge that is not routine, and cannot be memorized. However, the greater exposure to applying your knowledge you have, the better you are going to get at the harder questions. Better students are able to spot the shortcuts available producing more elegant solutions than their more workmanlike cohort.
Out of all the past papers, there has been a slight trend upwards in difficulty with the 2006 paper being the standout. Part of the reason why this was such a tough paper is that even the best students were struggling time-wise - and thus where usually the best students would have almost an hour for the final two questions, in this paper time for those questions was significantly reduced. So maybe avoid the 2006 paper until you really want to test yourself.
Best Regards
OldMathsGuy