As your child goes ahead in his school journey, his teacher will expect a higher degree of self reliance from him. And luckily, he is fully fit to be so, alongside starting his journey as an independent learner.
What you can do
During the summer break, allow him to do new tasks, take risks, act independently, and learn from his mistakes. Let him learn that yes, he CAN do things. For instance, if he is keen on making a sandwich, guide him about the things he will need and let him make it on his own. Let him try to complete a puzzle or word search in 10-15 minutes.
Practice giving your child verbal two and three step directions on a particular task. For instance, if he wants to make a paper boat, guide and show him how to go about it step by step. Then let him do it on his own. Provide opportunities for him to sit down and practice paper/pencil work at a desk area for 15 minutes or more. Along with fostering independence, this will also develop his ability to pay attention and sit for longer time to do projects when he starts first grade. Doing things himself will make him more comfortable with his new responsibilities at school.