That is a great question and one that requires a complex answer as there are likely many aspects to your SEO that need to be addressed. First and foremost, you should check to see if places like Google Webmaster Tools is giving you any specific messages. Google will certainly let you know if your site is not meeting their guidelines. Some people will receive an unnatural links warning or find themselves at the end of some other link-related penalty. In these instances, you want to take a look at the links coming to your site.
You can pull down a list of all of your backlinks through Google Webmaster Tools. From here you’ll want to sift through them and break them down into a few categories to make things easy. You are searching for bad sites, which usually consist of no page rank (not necessary 0 page rank), sites that are completely unrelated to your site, and look for foreign sites. Not all foreign sites are bad, however, a good number of bad links come from websites located in other parts of the world where it is more difficult to get them to comply to your desires to remove bad links. Now you disavow them using Google Webmaster Tools. This will not remove the links, however, this will make Google ignore them.
Next, you may want to check out that your own site isn’t sending mixed messaged to the search engines. If you’ve gone through a site redesign, make sure that all of your pages are showing properly. If you’ve removed links to certain pages on your old site that didn’t make it over, but did not unpublish them then those pages may be causing you some issue. If you do unpublish them then make sure that you have a proper, custom 404 page set up to let people (and search engines) know that those pages aren’t available anymore. The custom 404 page should include proper navigation so that people don’t get lost once they land on that page.
Another thing that you may want to check out is that your development site is not also being indexed as that is not something you want to happen. You also want to be sure that you are either using the www version of your site or the non-www version and not both. Set up a 301 redirect to make sure that people will be landing on the right version of your site. You don’t want to show two versions. You should also check to make sure that some older best practices are still good to use as they can be outdated and in desperate need of change.
Ultimately, you’ll want to check your site out to be sure that you’re sending the right message to the search engines. You should always check to see what problems your website might have even if you are doing really well in the rankings. As Ben Franklin is quoted as saying, “An ounce of prevention is worth a pound of cure.”
Written By: Doyle Clemence – SEO