My DS is in SGS Y7. He sat the old style tests that still included verbal and non-verbal reasoning. He practiced through Y5 taking part into a small tutor group. We felt that his tutor helped him with reasoning as well as with his essay writing. His school didn't do enough creative writing so some extra practise was needed there. We also made sure that he read a lot of books and not just adventure stories. Luckily he likes reading!
I think, like victoria123, that it depends on your child and the primary school they go to. I think the tutor kept the routine going and helped with exam techniques. He stopped going to the tutor quite early on in the summer and during the holidays he read a pile of books, wrote an essay a week and did some practise papers. Nothing overwhelming.
I hope this helps