The Smart Internet Marketer’s Google Penalty Recovery Plan

If your site has been hit with a Google penalty, the loss in traffic and
revenue can be absolutely devastating.  Some marketers might well choose
to scrap their site and start all over again (which isn't a bad idea if
your site isn't a monster), but for others who have a good flow of
traffic and great amount of reputation and subscribers, restarting isn't
an option.

So, what do you do if you're hit with a Google penalty?

Act Quickly

The first thing you need to understand here is that time is of the
essence.  The longer you wait to start recovering your rankings in the
SERPs and traffic, the more money you are going to lose (or not make,
same thing).  Further, your reputation is going to take a hit, meaning
even your most loyal clients might start wandering over to the other
side of the fence to see where the grass is greener.

Your first order of action should be to audit your entire website. 
Determine whether you have an algorithmic or manual penalty and then
pinpoint the cause.  That's the first area you should focus on. Typical
Google penalties include black hat SEO practices, buying links,
low-quality or duplicate content, high-bounce rates, on-page strategies
deemed manipulative, spamming and low-quality backlinks, so be prepared
to tackle those issues.

Depending on which update from Google caused the penalty (e.g. Penguin,
Panda, Hummingbird, etc.), your course of action will be dictated by the
latest fixes.  Take a deep look into your messages on your Webmaster
Tools account and look for communications from Google that might have
warned you (such as the Web Spam Team).

Take This Time to Fix Everything

Of course, you can just fix the problem as stated by Google and move on,
but it's much wiser to use this as an opportunity to clean up your
entire site.  Take a long, hard look at your practices – was this
penalty an anomaly or have you been toeing the line in terms of white
hat SEO practices?  Run an analysis on your site with Hubspot or Nibbler
and fix up any code errors, warnings or other problem areas that are
holding your site down.

Any backlinks (aka inbound links) that are coming into your site that
are low-quality or "bad" should be removed immediately.  This can be an
arduous process if you have a lot of links, but using tools such as
Moz's Open Site Explorer, you can expedite the process.  Using these
tools, check out all the websites that are linking to your site and
really evaluate which are "good" sites that are beneficial to your
ranking and/or business.  Get rid of any sites that might be bringing
you down (especially if those sites are the penalty trigger).  Don't
only remove these links, but construct a list of them and request Google
disavow them from your attributable backlinks.

Submission to Google

Once your site is completely fixed up, if your penalty was manual, you
can submit a reconsideration request to Google.   If your penalty was
algorithmic, you have to wait until the next time Google updates its
algorithms (this can happen a few times a day or once a week – Google
doesn't release this information unless it's a large update like
Hummingbird or Panda).  Either way your site's recovery is completely in
the hands of Google's team.  But by keeping a detailed record of all the
changes you made to come into compliance, you show that you are eager to
play by their rules.  Going above and beyond what you were penalized
will look good in the eyes of Google's team and you will likely be
reinstated to your former glory much faster than not.