He's managed quite well to be organised. One week he did lose a piece of homework and had to go and get another copy from the teacher and re-do it overnight. But generally he's managing well.
He has a clear plastic file (a robust thing not just a poly-pocket) where he keeps all loose sheets in his bag.
Then at home he does all his homework at the kitchen table and he has a box where he keeps any books he doesn't need at school next day.
When he's doing his homework he uses the equipment from his school bag and puts it back afterwards.
In his bag he has separate pockets for:
planner/basic pencil case
additional equipment - calculator, crayons, compass etc.
drink
wallet
emergency money
After he's finished his homework each evening he checks the timetable and packs his bag for the next day.
We also have specific hooks in the hall where he hangs his PE bag, tech apron, food tech apron, perf arts uniform, etc.
Crikey, it sounds like boot camp, doesn't it?
Obviously I've set up most of these routines for him, but he's maintaining them himself and it seems to be working.