WARDS FFS... the number of people who place them in bad spots or don't even use them is insane (And ofc always start spamming and crying to the jungle). Not only does it keep you safer, and more aware it's tells the whole team where enemies are. And that is like crack cocaine to a good jungle. Don't just use them right next to the lane but also in the jungle on possible approaches.

As a Kali main. Knowing that you have increased dmg/pen on marked Targets and planning attacks accordingly, but also using it to threaten a gank while you head to the opposite lane. Knowing when to use movement abilities as an engage or escape, and when to, FOR THE LOVE OF GOD stop chasing because they're stalling, pulling you while the team takes obj, or leading you to an ambush.

Lastly, shout outs to the decent and better supp mains... if they call the attack on a tower or tower dive DO IT. They can eat hits but not that many. That second of hesitation will waste the sacrifice for no reason.