Disable settings that prevent the Mac from sleeping or let it wake up overnight in your backpack and drain half of battery.
On top of those, it's probably best to not leave any USB thing plugged to the Mac before putting it to sleep (including YubiKeys).
sudo pmset -a hibernatemode 25
If you don't want your headphones or keyboard accidentally wake your Mac:
System preferences
> Bluetooth
> Advanced
> untick the last checkbox Allow bluetooth devices to wake this computer
System preferences
> Battery
> Battery
in left menu
System preferences
> Battery
> Power Adapter
in left menu
In Activity Monitor
you can check the most energy-draining apps, and whether they prevent sleep.
For example, when you play a YouTube video in a web browser, it prevents sleep.