Decrease in number of backlinks may be due to the fact that few of the websites where your backlink is placed may have been de-indexed by Google and so your backlinks are not being shown, as those websites are not present in the Google SERP results.
To increase the backlinks of your website, best thing is to approach for mix and match techniques and try to get links through various off-page activities like social bookmarking, forum participation, blog commenting, social media participation etc. After recent Panda update you need to tweak your strategies a bit in order to safeguard your website rankings. Follow these techniques to improve your website link popularity:
- Pay attention to the duplicate content that caused the fall in rankings after Panda Update and add unique and informative content that users are looking for.
- Limit the amount of ads on your website as having too many ads make it look like just made for adsense and can only hurt your rankings.
- Consider increasing the quality of your website and try adding few pages regularly to your website with some in-depth information so that Google crawls it frequently.
- Make your website all the time useful for visitors or in other words make it an authority on that subject.
- Increase your social media engagement as now Google tends to focus on amount of time your website is being shared on social media sites like Facebook and Twitter.