I haven’t done one for about 12 years but did lots before that.
some tips :
pack light, I mean REALLY light.
I used a 25l pack. better kit than I had allows less bulk.
use foil trays (the kind takeaways use) to cook with as they weigh nothing, fold small and can be thrown away.
take food that needs water adding (so it’s light) like porridge, super noodles and so on.
I always preferred using a rucksack as you can then ride the bike properly.
eat and drink all the time!
don’t miss the cutoff time by anything more than a couple of minutes as you lose loads of points.
we never took locks. I don’t think I ever saw anyone else with one.