The first couple days are the hardest for reading into posts. Some people have remarkable intuition, but for most people it's a matter of prodding and questioning people until you get something that doesn't make sense
For voting analysis, it's mostly a matter of knowing that the wolves know each other and the villagers don't. There are certain things that wolves don't usually do, like purposefully voting out roles wolves, that can provide evidence that a player is more likely to be a villager or the other way around, a vote like you had D2 where you tried to help out Shoveler looked like a wolf trying to protect another wolf. Of course it doesn't always work out, especially with veteran wolves. Not sure if reading through old games appeals to you, but the voting analysis done in this game has always been one of my favorites if you're interested in some pointers:
Breakout Kings: Werewolf Style (Game over - village wins) - Front Office Football Central