If your website has recently lost rankings for your important keywords, and this has subsequently lead to a loss of business and revenue, it is likely that this will be a result from an algorithmic or manual penalty that Google has imposed.
Each year, Google changes its search algorithm around 500–600 times. While most of these changes are minor, Google occasionally rolls out a “major” algorithmic update (such as Google Panda and Google Penguin) that affects search results in significant ways. Major algorithmic changes have had massive impact on methods of Search Engine Optimisation, which had been effective in the past. Whether through algorithmic filters or manual penalties, these alterations to the system has impacted how well your website organically ranks using the old approaches.
The whole face of Search Engine Optimisation has changed. With the methods that had previously worked wonders for your website being scrutinised by Google, it is important to fix any trace of old tactics and implement a new strategy to restore the traffic to your website. This process will require the removal of links, which conflict with the new algorithm and other strategies to let your website correlate with the latest algorithmic updates. The ultimate goal is to restore the effectiveness of your website and have Google’s penalty revoked.