Teachers of mine have strongly recommended for us to make a summary for certain subjects e.g. the content laden Biology, and to memorise and understand the major concepts.
Maths? Have to finish plane geometry in the holidays. (Was this a preliminary topic...?)
English: Read the texts on History and Memory and the poems.
Japanese: Finish off holiday essays
Knowing me I will look back at this post made prior to the holidays and laugh for believing I will be determined and not procrastinating.