I see two related issues:
1) study skills such as note taking (often Cornell notes but some prefer their own method, including doodling), reviewing (notes and source materials), analyzing, self-quizzing
2) ways to get ready for 6th grade might focus on executive function skills such as organization, prioritization, time management. NCLD is one source of information on executive function. Here is an image from Understood.org :
Camps can be a way for kids to practice study & organizational skills independently away from home while learning them. Yet for most kids, learning these things is not an event but a process. Coaching and support from parents who are aware of the specific approaches, techniques, and strategies can be helpful for ongoing reinforcement at home. From that perspective, having a book on hand to refer to can be helpful.