for 6s, main tips for med is just like
try to keep your scouts fully overhealed 100% of the time. your scouts should be positioning themselves so they're easy to heal. (really only applies if your scouts arent trash lol)
keep your demo/pocket fully buffed if you can (demo > pocket)
buff soldiers before they bomb
play with pocket/demo as much as you can
if your team is a hard scout carry, then feel free to be a little ballsy
make sure your pocket knows to call stickies so you dont drop to his mistake
be scared of everything. seriously.
it's best to keep your position from the enemy if you can. don't peak anything before your pocket or demo does.
from there it's just learning. med is a pretty easy class to learn mechanically, but it's hard to master. (ie, arrows, surfing off rockets, mlg ubers, etc)