All
Help them build good, active, revision habits. Remember revision is not something that happens just before an exam, it needs to be an ongoing process!
KS3
Encourage them to think of many reasons why things happen, this could be applied to any subject whether it be the news or the need for food etc... the habit of reading a book_any book would be beneficial for their development. At KS3 learners start to understand the thresholds and when they realise the requirements for "Mastery" in any topic they easily transfer it to new learning
GCSE
Encourage to them complete the quizzes found on this site on a regular basis
Get them to login to Kerboodle and try some exam questions. There is a section at the end of each chapter that focuses on exam skills.
Please see Curriculum Evening Presentation below:
Revision Guide: Chapter 1 Sample
Available in school from January 2018 for £6
Also available from Amazon
A Level
Encourage them to complete the quizzes found on this site on a regular basis
Get them to revisit Slides on GoogleClassroom for each topic
Suggest them attempt some example questions
An excellent article here: https://www.theguardian.com/teacher-network/2017/may/11/how-can-parents-help-students-survive-the-exam-season