Recently Google updated their algorithm to check layout of the web page and the amount of content that one can see on the page once they click on a search result. The page layout algorithm improvement demote those sites that don't have much content "above-the-fold".
If your website has been affected by this new update, you must work to gain the lost reputation again. And the very first thing you should consider is, how your web pages use the area above-the-fold and whether the page content is hard for users to discern quickly.
For this, there is a wonderful tool from Google, that can let you see how your website would look under different screen resolutions. And then you can redesign your layout for higher engagement and conversions. Check the Browser Size tool for the analysis.
Google Browser Size is a visualization of browser window sizes for people who visit Google. For example, the "95%" contour means that 95% of people visiting Google have their browser window open to the pixel size marked on the axis. This size is true client area without the title bar, tool bars, status bars, etc. Thus you can check which parts of your page were and weren't visible at typical browser sizes.
But the app may mislead you if you are having a responsive design that reflows as the browser width is adjusted. To examine such websites you need to manually resize the browser.
To try it, visit browsersize.googlelabs.com and type the URL of a page in the "Enter URL here" text box at the top of the window and click Go. The size overlay you see is using latest data from visitors to google.com.
Try Browser Size out on your website, and let us know if you will be changing anything because of this tool.