The way you get better at mafia is by playing mafia. Bad players are generally either those with certain style/commitment issues they refuse to address, or those who give up soon after trying.
That said, several of your actions were pretty bad, and could use some improvement.
In the beginning, you weren't really hunting scum so much as flailing around a bit. As a bit of a lesson, you'll notice Taricus was largely in the same boat- you stuck with it, he dropped out. Hence, you probably got better as the thread went on, whereas presumably he's not much better at mafia than he was when he joined. I assume you realize that interaction wasn't really productive now.
When you were in danger of being hammered, you still had a rather irreverent attitude, and more importantly weren't trying to find scum. You're lucky you weren't lynched.
Oh, missed that one.
Well, one has to wonder must wonder... If scum did notice such a post, would they not pay attention to it and try for two votes? There are two of them, and if they think I am going to vote for the first person to gather two votes, wouldn't they instantly team up to vote somebody out? It would make sense that is suddenly a pair jumped out of the woodwork ready to lynch, they would be scum. Although currently the only two votes together are against me, and I am not going to vote for myself, so we can assume they are either both too dumb to notice the chance, or two smart to notice it, we will never know.
Your WIFOM deserves special mention, for two reasons.
First of all, it assumes you know what the scum (or other players, for that matter) are thinking, which you don't. Some situations are more
likely than others- scum is less likely to hammer one of their own than a townie, for instance- but you really don't want to wager the whole game on the assumption that you know exactly how scum would act or react in a given scenario- most of playing scum well is
explicitly acting like they're not scum, after all.
Secondly, in this particular case it was an OMGUS, which usually doesn't look good. It didn't seem like anybody was especially upset with it, but responding to L-1 with "Everyone voting me is scum! Vote them instead!" usually looks like a desperate attempt at deflection.
This was pretty bad as well, because you once again assume that the hammervote must be scum if there's any scum left, which would mean scum would avoid it as blatantly obvious. You also give the bizarre explanation for voting Super as "That was in the past so I can't explain it, the point is that I'm still voting you and have reasons now." That's very bad, because you basically just admitted you had no reason whatsoever for voting Super at first.
Here is a notable post because it contains the same style of reasoning that led you to suspect Super, but clears major and indicts Okami... despite earlier claiming that Super and major were scum because if they weren't you'd have been hammered already. It's a nice example because it's both giving the wrong answer, which your earlier WIFOM wasn't (
not that you could have known that), and directly contradicts that earlier WIFOMy goodness.
As for what you did right... noticing how quick Super was to vote and how eager he was to hammer was good. That was more significant in a Vengeful than it would have been in a normal game, of course, but that particular part of your suspicions about him was well-founded.
I'm not sure how much of the plan this was, and it certainly wasn't quite the right way to go about it, but managing to piss off Super also served you well- he was far too defensive about you voting him without reasons. Again, acting scummy to rile up scum usually isn't worth it, and townies can become pissed as well, but one of the reasons people tend to be so vicious in-game is to get people acting emotionally.
So yeah. Drop the WIFOM and focus more on player reactions- you'll notice the player you were right about through the whole game was the one you were focused on for his specific actions, not broad generalizations about what scum would do in Situation X.