I know people do it but am still aghast that some start actually preparing in year 3... We used a tutor for an hour and a half a week in year 5 for both of ours (about a year before the exam). I think it's enough to give your child a fun, interesting childhood with lots and lots of reading, card and board games, plenty of stimulating conversation with adults and other children, lots of fresh air and exercise, and plenty of family visits to a wide range of museums, art galleries, theatre, sports events etc. We aimed to help ours develop an inquiring mind and a broad outlook on life whether or not they eventually went to grammar school. And to have fun with them too!
I agree this is the ideal. But a lot of people, for lots of different reasons, can't do or offer those things. And if you can do them, they can still fall into the category of:
-activities which develop a broad vocabulary
- getting to a good level in maths for her age - particularly rapid mental arithmetic as part of word problem solving
- developing reading comprehension
- spelling, punctuation and grammar