For DS we used the bond papers and the GL Assessment packs. We also found the bond 10 minute tests useful - though not all would agree
We practiced the timed sections and then also made sure they had some idea how long a certain amount of time was (if a section was 6 questions in 3 minutes we made sure that they had an idea of how long 30 seconds was) - we knew that for DS1 timing was going to be the thing and for the other we knew he would have a problem leaving a question that he couldn't do and moving on. It might seem a bit OTT but it gave them the confidence that they needed.
However for both DS2 and DS1 it was practice practice practice that got them there, they did something everyday all through the summer holidays and it worked very well as they both scored very well.