Holy Engagement! This was an awesome post, full of great info… and then I realized that 3/4 of the actual page was comments… which is even better for shares, SEO and overall engagement. I was lucky enough to attend an event where Neil Patel was giving some great blogging training and a lot of what you covered was there. https://www.thatbloggingthing.com/69-blogging-secrets-i-stole-from-neil-patel/ The simple fact that you comment back is awesome.
Robots.txt is not an appropriate or effective way of blocking sensitive or confidential material. It only instructs well-behaved crawlers that the pages are not for them, but it does not prevent your server from delivering those pages to a browser that requests them. One reason is that search engines could still reference the URLs you block (showing just the URL, no title or snippet) if there happen to be links to those URLs somewhere on the Internet (like referrer logs). Also, non-compliant or rogue search engines that don't acknowledge the Robots Exclusion Standard could disobey the instructions of your robots.txt. Finally, a curious user could examine the directories or subdirectories in your robots.txt file and guess the URL of the content that you don't want seen.
Thanks for bringing up this point - I agree Eric - competitive positioning can help you determine value that you bring to the table that your competitors dont.  I'm all for it.  Neilsen does some reports that provide awareness, likelihood to recommend, sentiment and other insightsfor your site/brand and your competitors. You can also pull some of that type of insight out of social listening platforms like NetBase, SM2, Radian6, Dow Jones, Nielsen, and so many others.  I've even done some hacked compeitove sentiment comprisons before using Search: searching for [brand or feature] + "like", "love", hate", "wish" etc. 

Description meta tags are important because Google might use them as snippets for your pages. Note that we say "might" because Google may choose to use a relevant section of your page's visible text if it does a good job of matching up with a user's query. Adding description meta tags to each of your pages is always a good practice in case Google cannot find a good selection of text to use in the snippet. The Webmaster Central Blog has informative posts on improving snippets with better description meta tags18 and better snippets for your users19. We also have a handy Help Center article on how to create good titles and snippets20.

The days when internet browsing was done exclusively on desktop PCs are long gone. Today, more people than ever before are using mobile devices to access the web, and if you force your visitors to pinch and scroll their way around your site, you’re basically telling them to go elsewhere. Ensure that your website is accessible and comfortably viewable across a range of devices, including smaller smartphones.
This philosophy is beautiful in its simplicity, and it serves to correct the “more, more, more” mentality of link building. We only want links from relevant sources. Often, this means that in order to scale our link-building efforts beyond the obvious tactics, we need to create something that deserves links. You have links where it makes sense for you to have links. Simple.
Google is the most popular spider-driven search engine. Its database currently has about 4 billion pages indexed and is known for finding the most relevant information. When Google spiders the Web, it finds sites by traveling through links. The more sites that link to you, the more important the engines believe your content to be. You should focus on getting many important sites to link to your site. You can do this in many ways: submit to online directories, exchange links with business partners and industry-related sites, or participate in Link Building.

Black hat SEO involves techniques such as paying to post links to a website on link farms, stuffing the metadata with nonrelated keywords, and using text that is invisible to readers to attract search engines. These and many other black hat SEO tactics may boost traffic, but search engines frown on the use of such measures. Search engines may punish sites that employ these methods by reducing their page rank or delisting them from search results.
Inclusion in Google's search results is free and easy; you don't even need to submit your site to Google. Google is a fully automated search engine that uses web crawlers to explore the web constantly, looking for sites to add to our index. In fact, the vast majority of sites listed in our results aren't manually submitted for inclusion, but found and added automatically when we crawl the web. Learn how Google discovers, crawls, and serves web pages.3
Search engines use complex mathematical algorithms to interpret which websites a user seeks. In this diagram, if each bubble represents a website, programs sometimes called spiders examine which sites link to which other sites, with arrows representing these links. Websites getting more inbound links, or stronger links, are presumed to be more important and what the user is searching for. In this example, since website B is the recipient of numerous inbound links, it ranks more highly in a web search. And the links "carry through", such that website C, even though it only has one inbound link, has an inbound link from a highly popular site (B) while site E does not. Note: Percentages are rounded.

Fortunately, Google puts more weight on the anchor text of external links anyway. So as long as some of your external links have your target anchors, you’re probably OK with a “Home” button. In fact, I’ve ranked homepages with a “Home” anchor text nav button for some seriously competitive terms. So it’s not a make-or-break ranking signal by any means.