My DS took the 11+ last October. He understood the question types really quickly but just couldn't do the time - it was the same at school, as soon as he knew he was being timed he froze. We tried several techniques - how fast could he do 10 questions (and then add up the times at the end), how many question could he get right in 10 minutes, I gave him papers to do "in his own time" but secretly timed him and showed him afterwards how much spare time he had. It all came down to his confidence in his ability. After the summer holidays (i.e. just weeks before the tests) he went completely off the boil. We both knew he could do the question types but he needed some kind of incentive to work quickly. The method that worked for us was basically a race between the two of us - we took one question at a time and we just shouted out the answer. It became a matter of pride for him to beat me. Obviously he would always win overall but I did make sure that he didn't win at each question
. We also the 11+ Exams CDRom which gives timings for each question - again the incentive was to beat his personal best.