Use your mouse to resize your browser and see what your browser size is. The numbers located inside of the box will tell you how many pixels your browser is. Knowing your browser size will allow you to set up your site so that it can be viewed on different sizes of monitors while still displaying all of the important information you wish to convey to visitors.
Stop building your SEO strategy around algorithm updates. In search, Google’s goal is the user’s goal. Instead of chasing an algorithm that won’t stand still, place your attention on content that aligns with your user’s intent. For example, HubSpot placed a heavy emphasis on winning featured snippets for important keywords because of its real estate and the great user experience they provide for the user. Here’s how we did it. 
If you're looking to upload an image to a blog post, for example, examine the file for its file size first. If it's anywhere in megabyte (MB) territory, even just 1 MB, it's a good idea to use an image compression tool to reduce the file size before uploading it to your blog. Sites like TinyPNG make it easy to compress images in bulk, while Google's very own Squoosh has been known to shrink image file sizes to microscopic levels.
For example, we regularly create content on the topic of "SEO," but it's still very difficult to rank well on Google for such a popular topic on this acronym alone. We also risk competing with our own content by creating multiple pages that are all targeting the exact same keyword -- and potentially the same search engine results page (SERP). Therefore, we also create content on conducting keyword research, optimizing images for search engines, creating an SEO strategy (which you're reading right now), and other subtopics within SEO.
As I had a teacher at school who was always really picky on how to draw conclusions I must say that the conclusions you drew for your health situation might be true, but dangerous. For example: If slightly more women than men suffer from health deseases it could be wise to write the information toward women. But, if you take search behaviour into account thing could look a lot different: It might turn up that men search more than women or that (senior) men are more present on the net than women.
Your blog provides a great way to build a personal relationship with customers and prospects — and to gather their email addresses. Consistently end blogs with a call to action that encourages readers to sign up for your email messages. Require blog visitors to provide an email list in order to leave comments, and set it up so that they have to actively opt out if they don’t want their email address included on your mailing list.
I completely agree that defintion of a target audience isa great first step, but would ask if adding in competitors to the analysis (mentioned here as a later step) helps draw out who your target audience would be via comparisons, i.e. showing who you are an who you are not - would be very interested to hear opinions on how this tactic can be used within the overall step in coordination with targeted keyword discovery.