There are over 20 parameters that decide the success of a website. But from competition point of view you should focus on the sources that are backlinking to your competitor’s site.
When i launched social media page for my website i used video marketing to get more fans and followers. You have to share content on your social media page that is engaging to get more fans.
With social media marketing you can get a lot of traffic to your sites and generate leads. When done right SMM can also be very helpful with brand awareness promotion.
In 2018 digital marketing is seeing a major shift after the mobile-first indexing is fully rolled out by Google. You need to focus on this latest update and include it in your digital marketing strategy.
Negative reviews used by competitors to tarnish your reputation is nothing new. I faced the same troubles with my website. The best you can do is to notify Google and you already did, rest leave it up to them.