The thing about SEO in 2018 is that Google changes its algorithms more than once a day! Reports say that the company changes its algorithms up to 600 times a year. While the majority of those updates consist of smaller changes, among them is the occasional, major update like Hummingbird or Panda that can really wreak havoc with your traffic and search rankings.

Paid search advertising costs money, which at first may seem like a disadvantage, but these costs can easily be managed. With cost-per-click (CPC) or cost-per-thousand-impressions (CPM) campaigns, you spend as much or as little as you want. You can adjust your campaign budget at anytime, so if your business is going well, you can spend a little extra to drive traffic to your website and catch the attention of new customers.
Another tip you can use is just reach out to the prior agency and say something like the following: “We realise you were using link networks for our website which has resulted in a Google penalty and loss in business. Can you please remove my website from any link network you have built?”. If the prior agency is decent, they will remove the links from the network.

Google doesn't always include a whole paragraph of text in the Featured Snippet. If you add "Step 1," "Step 2," "Step 3," etc. to the start of each HTML heading within your content (for example, within your H2 tags), Google will sometimes just list out your headings within the Featured Snippet. I've started to see this happen more and more in keywords beginning with "how to".
To avoid undesirable content in the search indexes, webmasters can instruct spiders not to crawl certain files or directories through the standard robots.txt file in the root directory of the domain. Additionally, a page can be explicitly excluded from a search engine's database by using a meta tag specific to robots. When a search engine visits a site, the robots.txt located in the root directory is the first file crawled. The robots.txt file is then parsed and will instruct the robot as to which pages are not to be crawled. As a search engine crawler may keep a cached copy of this file, it may on occasion crawl pages a webmaster does not wish crawled. Pages typically prevented from being crawled include login specific pages such as shopping carts and user-specific content such as search results from internal searches. In March 2007, Google warned webmasters that they should prevent indexing of internal search results because those pages are considered search spam.[46]
BrightEdge research supports that a blended approach is best for delivering high performing content. Not only will combining organic and paid search increase website traffic, but it will offer a bigger return on the investment. Take Retail, Technology and Hospitality industries, for example — organic and paid search combined make up more than two-thirds of their total revenue.