Having had the gruelling privilege of articling on a few murder trials, I have compiled the folllowing list of hopefully helpful tips:

Follow your Crowns around all day, especially on breaks and after court. Your Crowns will not tell you what they are thinking about the case and as soon as you get out of court (break or for the day) is when everyone re-hashes what they think happened in there. The most interesting part about this is that (for me anyway) what I thought happened was never really quite what anyone else thought. Incidentally, no one’s version is ever the same. What arises out of these discussions is usually a plan of sorts, knowing the plan or at least what people think so far helps to better understand what is actually happening when you are in court watching (see #2) and anticipating issues (#3). Added bonus with following them around after work is there may be a glass of scotch in it for you. (Start drinking scotch.)
Be in court all the time. Be seated somewhere where your crowns can see you so that if they need stuff they can pass you a note.
Try to anticipate issues before they arise or as they are arising. Having a seminal case or two (with you in court) on an issue that you think is coming down the pipe really helps. If you have something good and relevant on you and you think it can help your Crowns in that moment, highlight the para in the case and hand it up there.
Read all the witness statements, transcripts, intercepts, etc… before the individual testifies. This is hard, but that way when a witness says something that you know is not consistent with their statement you will be able to point it out to your Crowns. Have those prior statements with you when witness testifying (don’t need to do this for expert witnesses) Most of the time your Crowns will have already found the inconsistency but it’s a really good way to be well versed with the case.
Ask your Crowns to read their trial binders and if they have a moment to explain to you what they’ve done and why (in the binder).
Don’t wait until morning to do anything. If you have been asked to prepare something for the next day, do it that night, something will come up in the morning that will prevent you from getting it done.
Don’t take notes about the evidence in court (unless they ask you to) take notes about process, procedure and strategy. Ask questions at the end of the day about this stuff (if you don’t write it down you will forget, too much happens and by now you have stopped sleeping, have developed a taste for scotch and can’t remember when you last ate…)
Don’t talk to anyone (defence counsel, court security etc..) about any details of the case that you are privvy to, even things that seem kind of innocuous.
Talk to your cops and offer to help them too. They know more about the case than anyone else and especially for the I/O who will likely testify they are not only assisting in court but also preparing to testify. If you can sit in on Crown prep with the I/O, this is an unbelievably cool thing to watch and learn from. (note: the I/O will usually testify last) They are also the ones making sure witnesses are lined up for the next day and they always know what’s next.
Ask lots of questions, as a Crown you will rarely have the chance to watch others in court and learn from them, take advantage now.