Can you tell me what major areas & ranking factors of Google local SEO should be focused first and foremost?

From the viewpoint of organic optimization for regionally-targeted online search, as well as Google local SEO in particular, there aren’t too many spheres of your website performance or primary ranking factors for you to emphasize beyond all. Taken in general, the whole area of Google local SEO, with its major ranking signals, is actually falling into just three primary categories pulling together the following factors of your website performance: On-Page Factors, Local Links, as well as External Location Signals. That being said, below I’m going to quickly outline each of them in greater detail. 

Google Local SEO: Top 3 Factors Determining Your Ranking

So, here are the major factors and primary areas of your website performance to be focused to improve your online visibility and positioning in Google’s local organic search listings. Basically, all these elements will have a generally positive impact (of course, when done right) on your local ranking potential – therefore the following ones are to represent your main areas of focus. Here they are.

On-Page Factors

Given that we don't want to really over-technologize this area of local SEO, just make sure to piece together the following key on-page elements. Before anything else, Google is looking at your Title Tags, Meta Descriptions, H1/H2/H3 Header Tags, as well as On-Page Images and Body Content itself. Also, there are are some other specific elements to be found directly on your web pages, such as Google Map (homepage/custom landings), Business NAP Data (ideally, to be placed on every page and well-structured with schema.org markup). And finally, remember about these specific elements, which are related namely to your business credibility among the target audience – you should consider User Testimonials, Accreditations, and External Reviews over there. That's it.

Local Links

Given that this is a particularly specific category of Google’s local SEO ranking factors, let's cover the main points of your focus just in general terms – simply because the right links are always dependent on every given case and type of the business. So, ideally you should comply at least with the following basic link factors, such as Location-Specific Links (i.e., any form of credible and relevant source within your location will do), Industry-Specific Links (i.e., a directory or third-party website section, which is real, topical, and relevant to your business or location you're serving with it), as well as Authority Editorial Links (i.e., creating some deserving articles/posts to attract some true editorial links from local websites/blogs bearing the highest Domain Authority/PageRank scores).

External Location Signals

The thing is that Google tends to get the main NAP data on your business website correlated with the information submitted to your Google My Business dashboard. Ultimately, to make every shred of data validated with the rest of your related business information found across the Web. It means that there are just two key elements for your consideration to that point, such as NAP Data Consistency (it may seem like a no-brainer, but maintaining a consistent location fingerprint is the matter of critical importance, of course, if you want to rank well locally), and Business Citations (similarly, you should be consistent when getting your business listed on yellow-page-like online directories and social media platforms). That way, remember to have any duplicate/outdated information instantly cleaned up – and you're done!