I'll preface this by saying that I don't belong to HMCS
Venture, so I don't know exactly what readings are on the current curriculum there. But I have a pretty good idea of what you need to be successful.
Without a doubt, the single most useful document to be intimately familiar with as a Command-stream NWO between now and your promotion to Lieutenant-Commander is the
Collision Regulations (C.R.C., c. 1416), aka "COLREGs". This is the NWO Bible. While assessment standards within the naval training establishment ebb and flow, knowing the important rules (i.e., the "Interpretation" section, and Schedule 1 - Rules 1-19) verbatim will greatly help you, both during training and with the Captains that you'll sail with.
Knowing this much text by heart isn't easy, and the ability to recite verbatim fades quickly. It's better to study small amounts of it regularly rather than trying to cram all at once. Any memorization you do now will only make life simpler over the next decade. With the exception of the Canadian-specific modifications, these rules are international. As such, there's ample free training available on the internet that can help you visualize it all, especially lights and shapes. As well, a book that you'll encounter during training that really helps to contextualize these rules is
A Guide to the Collision Avoidance Rules, colloquially known as "Cockcroft". A word of advice - you'll be issued this during training for free; if you want a personal copy do not pay full price for this, as there should be a number of used copies available either online or locally in Victoria for a much cheaper price. Older versions are just as good.
If your brain starts to go numb after trying to remember all of the Rules, the pop-science book
Thinking, Fast and Slow by Daniel Kahneman is pretty well regarded by myself and a number of peers for being relevant to the profession. Just understand the usual caveats for any science-turned-bestselling book.
Hopefully this helps. Feel free to reach out with any questions.