(which is why I'm confused about a poster writing references now?).
references are rarely down to one person, you collect a short reference from as many staff as possible, and edit them and combine them.
Producing a reference takes the school a long time!
I'm leaving in the summer, so every partial reference I am contributing
has to be ready and with the tutors before I leave.
Even people not leaving the school will be writing their bits of references now. You need to do it whilst the student is in front of you, really, and you need to be able to ask them things. What are they apply for? What are they highlighting in their personal statement?
what do they want you to mention? etc. Some applications will be submitted in September, but some not until January. Even without leaving the school it is very possible not to have seen the student for 6 months, and have very hazy memories of them by then.
If what I write is no longer applicable, because the student has changed their mind about what they are applying for, or something, then their tutor will edit my comments before the final draft.
Writing a reference, as a contributor or an editor, i ask the student things like
What aspect of the course have you enjoyed most? What are you mentioning in your personal statement? What do you consider your strengths? What have you contributed to the school/ class over the last few years. What have you contributed to the wider community? What reading and activitiies and open days have you done? What aspect of the subject can you discuss with me, here and now, that you haven't specifically been taught, but have researched alone, etc
The other reason to start early is because quite often, a student will not have contributed ANYTHING to their school or community, then are dispatched off to contribute something, ans told to return later having contributed.
(Some students surprise me though, one real PITA student who I guessed would be a non contributor in fact came out with a huge list of things they had done for other people over the past year - it all checked out and was very impressive)
Likewise, if a student has done no activities, independent reading, etc, they will need to do this before either the reference or the personal statement can be completed.
This is where open days, etc, come in. Just turning up to an open day and wondering around, not so much, but for example attending a specimen lecture at an open day and being able to discuss the content is the best possible way of showing you are someone who will be able to enjoy and benefit from the lectures of staff in that department.
Of course, if students have no contributions to the school, I am able to help them identify some opportunities, likewise with reading. But open days are largely down to sorting it out for yourself! Schools may arrange the occasional one, but its the individual students who need to organise themselves for the rest.
Sixth forms are able to award bursaries to families with an income of under 45k (both parents income combined normally, even if parents are separated) and one grounds for this is coach fare to open days.