April 21 Google mobile ranking update
Google the search giant is constantly updating it's search algorithms.
With mobile devices becoming more popular, people tend to browse the web more with these devices, most websites however are not responsive (mobile friendly)
The upcoming "mobilegeddon" update will have great impact on your website's ranking, if your website is responsive (mobile friendly) or has a mobile version it will be ranked higher.
If it doesn't however, your site ranking will decrease.
Check all pages of your site, a responsive homepage doesn't necesarily mean the rest of your site is mobile friendly
Optimize images on your site for web
Use the google webmasters site crawler tool to fetch & render your site:
Check the render results:
If the page rendered by google seems broken/unstyled use the robots.txt tester to find out what is blocking google from rendering the site properly:
Here you can see the stylesheet and images are not being rendered properly because they are blocked by robots.txt
Use the robotx.txt tester tool to troubleshoot the robots.txt file
Delete the lines marked in red or specify custom allowed directories and test the file again.
Apply the changes made to your site's robots.txt file.
Fetch & Render your site once again:
This time the site rendered properly.
Note: The fetch & render tool can also fetch & render mobile versions of your site