Skywars is one of the major games which require a good inventory organisation, as you quickly loot chests. Below is where i put items in my first 9 slots.
Slot 1 : Weapon
Slot 2 : Bow (if no bow, trajectories, ex snowball)
Slot 3 : Trajectories
Slot 4 -5 : Blocks
Slots 6 - 9 : Food, pots, and...