Extra work during summer holidays for Computer Science

Heya everyone! I am a L6th student going to be U6th in September, and I'm looking to hopefully go to top unis in the UK when I graduate. It would be ideal to bump my predicted grade for Computer Science up to A* so I have a better chance at applying, and I would like to ask what I could do during this summer to prepare. I am currently planning to do virtual work experiences, do a MOOC, and to also do some readings. Does anyone have advice on what else I could do? Thank you so much!