Join the class Whatsapp, it may be a life saver for last minute comms and for getting to know the other school mums in cases of emergencies.
Not every child is shattered - those that have been in regular nursery/childminding (with longer days) will probably adjust better but I've found Year 1 was the time my son got more spun out as work was increasing (rather than just playing).
Bring a snack to the school run if you've got a walk/journey home.
Label everything - particularly if your child likes shedding jumpers as soon as they get in. You don't need to go all out for uniform but I'd recommend a decent number of polo shirts because they get filthy.
If you suspect SEN, speak to the SENCO early doors and raise your concerns. Some schools are very hot on it, some are not.
Some children regress a little when they start school, so things like bed wetting, bum wiping, even things like settling to sleep can take a bit of a hit but usually iron themselves out eventually.
Situational and specific to the child, but if your child is one that gets quite tired I recommend setting aside on day at the weekend where they can just wind down and do something lowkey.
You'll get emails daily/multiple times daily about all sorts.
Your child is just one of 20/30 and feedback doesn't really happen unless major incident/issue or at parents evenings. This threw me completely as we'd have daily feedback from childminder but soon became the norm!