I did some creative writing tasks with DD once a week over the summer hols. Givng her short pieces on quirky topics to write (for 30 mins) then analysing them together - looking at sentence structure, vocabulary (and suggesting alternatives), grammar etc. Weirdly, she found it very exciting to let her imagination run wild!
For Wimbledon prep - loads of practice of VR & NVR test papers, so she got the hang of the techniques. (if they are still only doing these papers - not sure if new Head has changed test since this January)
We also did past papers from various other schools. Starting with the 'easier' papers (10+ from Emanuel for example), to help boost her confidence and graduating on to harder papers. We didn't really focus on speed until Xmas hols just focussed on understanding concepts and accuracy first. Also,discussed (multiple times!) technique of answering maths and comprehension papers to get max points. Took a while for her to understand that.
We are further south but I have experience of SPGS, JAGS, Alleyn's, Wimbledon, CLSG which I'm happy to share. No, she isn't a musical whizz - violin & piano Grade 1 which we didn't even bother to mention on any application (and wasn't asked about at interview); doesnt participate in art or drama in any way (does ballet); keen on sports but didn't go for sports scholarships. Can only speak English - no aptitude for language no matter what we try. Good all rounder in maths and English; hard working normal quirky (aren't they all!), quite confident 10 year old. Got offers to all but I won't say where she's going, as that may 'out' her.
We just went for it and hoped for the best. She seemed to enjoy the process because we didn't make too much fuss about it but always made the prep stimulating and challenging, in a good way. We didn't apply for any state places (foolish of us, because we honestly didn't know how stiff competition would be and there really wasn't a viable option in our area. In hindsight, I may have slept more soundly over Xmas and new year if I knew we had applied and at least she would go,'somewhere'). We had a tutor in the summer who was brilliant at discussing books and brining out her ideas. Getting her to explore characters' feelings and 'layers' within stories. Kind of books they read together- My Family and other animals, boy in striped pyjamas, Alice in wonderland. They basically chatted about books for an hour with the tutor asking probing questions - this REALLY improved DDs ability to hold interesting conversations with a 'stranger' and I think this helped greatly with interviews. She read voraciously (in prep for chats with tutor); and she's also an avid reader of BBC's Focus magazine, Guinness book of records and First News. Which also helped with interviews and creative writing. Tbh, we panicked a bit as we never really watch TV or did puzzles / crosswords with her. But she was fine. She had some interesting interview discussions (where I thought she had definitely blown it e.g. By telling her interviewer that rules are there to be challenged or broken; and she sometimes deliberately pretends she can't hear me).
Do the prep gently. Don't panic or vent frustration in front of DC. From what I've seen on MN and Eleven Plus forum, every DC seems to get a place. The angst and agro arent worth it, in hindsight. Just ask as much as you can on here, as I found I got more out of MN than I ever got from any mums in RL.
One thing I would have done differently... I would have chatted more to DD about logistics of exam days. She was thrown by the fact that so many (up to 700 or more for some) kids were also sitting exams at same schools and some of those kids looked really stressed. She'd never seen so many children at once! (Her primary was tiny) or seen such anxious / stressed child and parent combos. Some parents were even pushing others out of the way or swearing over parking. That threw her confidence a bit and I had to give her a mini pep talk on the spot. She was fine.. But I could have spared her that bit of angst on exam day!