Ever since its April 2015 update, Google is now taking the user's mobile experience into consideration in its search results. This means that when a user is doing a search on a mobile device, Google's search results will favor websites that are mobile friendly over the ones that aren't. If you want to capture that mobile search audience, you will need to have a mobile version of your website in addition to your desktop version.
How do you figure out what keywords your competitors are ranking for, you ask? Aside from manually searching for keywords in an incognito browser and seeing what positions your competitors are in, SEMrush allows you to run a number of free reports that show you the top keywords for the domain you enter. This is a quick way to get a sense of the types of terms your competitors are ranking for.

Black hat SEO attempts to improve rankings in ways that are disapproved of by the search engines, or involve deception. One black hat technique uses hidden text, either as text colored similar to the background, in an invisible div, or positioned off screen. Another method gives a different page depending on whether the page is being requested by a human visitor or a search engine, a technique known as cloaking. Another category sometimes used is grey hat SEO. This is in between black hat and white hat approaches, where the methods employed avoid the site being penalized but do not act in producing the best content for users. Grey hat SEO is entirely focused on improving search engine rankings.
If you're a regular blogger, these are probably the topics you blog about most frequently. Or perhaps they're the topics that come up the most in sales conversations. Put yourself in the shoes of your buyer personas -- what types of topics would your target audience search that you'd want your business to get found for? If you were a company like HubSpot, for example -- selling marketing software (which happens to have some awesome SEO tools ... but I digress ... you might have general topic buckets like:

Hey Sharon, great post! Re. dwell time – I’ve read conflicting opinions, some saying that Google DOES consider it an ‘important’ ranking signal, and others saying that it doesn’t, because dwell time can sometimes be a misleading indicator of content quality. For example when a user searches for something specific and finds the answer immediately in the recommended page (meaning that the content on the page is actually spot on) so he returns to the SERPs very quickly. I have been unable to locate any definitive statements (written/spoken) from anyone at Google that suggest that dwell time IS still a factor in ranking considerations, but it makes sense (to me, anyway) that it should be. Do you have any ‘proof’ one way or the other re. whether Google definitely considers dwell time or not?
So if you think about it, SEO is really just a process of proving to search engines that you are the best site, the most authoritative, the most trusted, the most unique and interesting site that they can offer to their customer - the searcher. Get people to talk about you, produce good quality content, get people to link to you, and Google will be more confident that you are the best result that they can offer to their searchers, and that’s when you will start ranking on the first page of Google.

Heading tags are the title elements that you can use to separate your text content. These headlines give search engines a better understanding of what your page is about. Plus, people tend to go through the headings first to see if your content is what they're looking for before actually reading it. So, you want to use headings to your advantage and make sure they're descriptive and explain what your content is about.

This is why developing a list of keywords is one of the first and most important steps in any search engine optimization initiative. Keywords and SEO are directly connected when it comes to running a winning search marketing campaign. Because keywords are foundational for all your other SEO efforts, it's well worth the time and investment to ensure your SEO keywords are highly relevant to your audience and effectively organized for action.