The physical side
Something I regularly tell all our language learners that if it’s possible go to a language session after you do some sort of physical activity.
It’s not some great discovery that I can take credit for, it’s a scientific principal that you’re brain isn’t going to function right and learn much unless you’ve got blood flowing through it.
You won’t be able to retain anything if you’ve been in a sedentary position for the past 5 hours and then turn on your computer and go to a session.
Get up jump around for a bit before, even better go to your language session right after hitting the gym or after sports. It’ll monumentally improve your cognitive ability and get your dopamine and epinephrine levels high that radically improve learning.
Just like you want to make sure you’re in a optimal state when you work out so you can maximise the effect your training has on your muscles, same with a mental workout.
Make sure your physically ready, have some fresh air, drink plenty of water, and are in an optimal creative state so you can get the most out of the time you spend learning.