Google always wants to make sure that the most qualified pages are showing up in their queries. This makes sure that users get the most relevant sites regarding content, combined with the best navigation and ease of use. Its quality score is an estimation of how relevant your landing page, keywords, and ads are to the keyword you’re targeting. It also relates to the people viewing your content, where your ad will be located on the page, and how much Google is going to charge you for your ad location.
High quality scores (7-10) result when Google deems your landing page, keywords, and ads as something worthwhile for people to check out. It means that each of these things are useful and highly relevant to the keywords you’ve purchased. The great thing about high quality scores is that they lower your click costs.
Low quality scores (1-5) happen when the same sources mentioned above is held in low-esteem by Google, because it regards your site as non targeted or irrelevant to viewers.
Keywords are essential to your quality score, and some effective ways to use keywords to your benefit are: keyword choice, grouping similar words together, and selecting the right amount. Your ads should be highly targeted, and make sure your landing page is based on these three factors: relevant and original targeted content, transparency, and ease of navigation...
Via Lauren Moss