Theory post incoming!
One of the main things I watch for is narratives. Playing scum is kinda like telling a story, and I note scum tend to have a fair bit of influence over the game. This can be screwed up a little by good/loud players, and it's part of the reason I'm skeptical of my read on you, because you're definitely in the latter, and I gather you're not bad either. (This is not my full thoughts on you, if there's any doubt. That's not coming before tonight at the earliest.)
I also like to look for signs of deliberate positioning. This tends to be more subtle than not, because scum tends to be self-aware enough to disguise them.
I really like to get to know players, their personalities, and how they think. I tend to be more of an observer early on, and then dive into the game when I have a strong read. (Bro should be able to confirm, and BRantz might be able to. I've gotten better since then, and can manage a micro/normal relatively early on, but this is a whole different ball game.)
I also like looking at wagons over the initial reads, because I don't actually learn too much about the people getting scumread. It's the people voting/waffling/disagreeing, etc who're telling me the most about themselves.
That's a quick overview of me. So, tell about yourself.
I'd appreciate getting I was a bit skeptical of this Bulbasaur read early on, because while I could agree they needed more activity, and was cool with pressure votes, I disliked the way it turned into a solid scumread after continued absence. It felt like you'd found a comfortable spot, and stuck with it.