Getting into selective schools

Hi guys! Hope everyone’s staying cool and hydrated on this VERY hot day.

I was just wondering if anyone here has got into/knows people who’ve sat the selective school test and got into one of the schools. Im currently helping my little brother for his test next year and I’m not sure what else to prep for. He’s in tutoring and did all the past papers so I’m not sure where else to go from here. Anybody have any tips that’ve helped them succeed? Much appreciated!

Thank you!