Google put out a new Webmaster Help video today. This time Matt Cutts talks about what to include in a reconsideration request, which you may have to submit if Google has caught you violating its quality guidelines.
"The goal of your reconsideration request is to, number one, to tell Google you've stopped whatever violations of the quality guidelines were happening - paid links, cloaking, scraping, you know, doorways - whatever it was, you need to make a clear and compelling case that that has actually stopped," says Cutts. "That behavior is no longer going on, and that you've cured that as much as possible. So, if you were doing paid links, you've gotten as many of those paid links pulled down as you possibly can."
"The second aspect of a reconsideration request is to basically give us a good faith assurance that it won't happen again," he continues. "You don't want to say, 'Oh, well this site looks like it's reformed, okay, we're going to lift this manual action,' and then they immediately go back to spamming or doing their old tricks. So, what you want to do is step into Google's shoes, and say, 'Okay, what would best convince Google that we've turned the corner, and this behavior has stopped, and that we've cured whatever was going on, and it's not going to happen again.'"
"Great things to include: things like details of the sorts of sites that you were contacting if you were removing links, for example, if you used an SEO, and they really just shot you in the foot because they were doing all sorts of unethical things...that's the sort of thing where I would give us details about that," he says. "Tell us about the link network or the SEO."
The more stuff you can include to make your case, the better chance you have of success.