The first time I really got better as scum was Good vs Evil, Chaos vs Law. Before (and during the beginning of) that game, I was not a scum leader; I was following the directions of MoS, who I trusted to guide us to victory.
But then, MoS got nightkilled, so I was left to fend for myself. That game was the first game where I profiled players: I did threat assessment, using what I knew off of them in general AND off of what they had given thusfar, to paint out a picture, a prediction, for what they
The odds were stacked against me, so I got lynched in mylo, but it was still the game-changing moment which sparked the series of scumgames I'm known for: Anything Goes, Left 4 Dead, Attack on Titan (okay, so we lost that one, but it was a close game and give credit where it's due: prior to me coming in, all three scum were the leading wagons; after I did, the town mislynched D1), Paranoia Mafia, Inorganic Chemistry, and maybe some others. All of them took from that one moment, using what I would later dub Situational Awareness: knowing what position you're in, and manipulating it such that your team is in position to win.
There were two moments that triggered me getting better as town.
One, the moment where the type of analysis I did changed. When I stopped focusing on the surface level stuff (what a person was saying, and arbitrarily from some mathematical standpoint assigning it a value of "hey, that comment is town/scum") and instead focused on the psychology behind the player, my accuracy improved. I went from "that action is scummy/townie" to, "Hey, player X is doing that action, but I can't understand why. It makes sense for Y to do it, and if Z was doing it I'd think Z town, but X doing it makes no sense at all", more or less.
Two, the moment where I stopped lying to others about the above change and was just upfront about it, if necessary admitting gut rather than trying to lie my ass off to come up with some logical reason why this person who is obviously scum would be scum. That was the moment I became more charismatic.
But the thing is, true to both town and scum games is...after a certain point, things become cyclical: what you need to do in each game is different from the last, so there's no true "point of improvement". The game's so ever-changing that something which improved your game last time will significantly hinder you next time, and on rare occasions you can get vice-versa.