Hi!
I did two one week long vac schemes in 2020, and generally all the advice myself and other people have posted on this thread is still extremely applicable. But more specifically, I think the outcome of shorter schemes (i.e. whether or not you're made the TC offer) are more focused on:
a) The quality of work you produce whether those are fixed assessments/work your supervisor gives (side note: both my one week schemes only had fixed assessments and no real live work - there's a good chance you can expect the same);
b) The final exit interview - because it's a shorter scheme and there's less opportunity for associates etc to get to know you and give feedback on you I think a lot of it comes down to the impression you make on your interviewers at the end. You can see advice I've given on exit interviews here. Again because the scheme is much shorter, I think its fair to say the kind of questions you get asked will be more competency/motivational focused rather than reflective questions (again see the previous link for the difference between the two);
c) How engaged you are - are you asking questions during presentations, taking notes etc. You can prepare for this by looking up questions that you'd like to ask once you do get your schedule for the scheme. Personally, I'd recommend just asking genuine questions based on the content of the presentation (rather than preparing what you think might be impressive questions) but I also know sometimes doing the preparation work can help with confidence.
Because these schemes are way shorter I wouldn't get too caught up in setting up calls with lots of different people or going out of your way to take on extra work. You'll find that there will be lots of presentations, socials, networking events etc. set up back to back and you'll hardly have the time for anything extra So I would focus on the aspects I mentioned above. I hope that helps!
