There are 3 key signals that Google is watching today.
Good content / text content onpage
Good technical compiled website with thoughtful url structure
Good link structure both onpage and offpage
Google thinks this is good, so traffic increases to your side and commitment. This makes you move forward and get good faith that you have a relevant webpage with information that people want in your area.
Over 200 different parameters search Google through. The more of these are optimised for better visibility. The greater the competition is that more of these 200 must be optimized. Therefore, if you 6 months ago did a SEO optimisation then maybe it needs to be built on today. If you search engine optimize locally in your area and then relax, it may happen 3 to 6 months after that, competitors have passed you in position.
They may be able to pin in the 15 most important points of the 200 parameters Google wants optimized, but you're still on 10 points that worked. Now, you have to run back on competitors again and optimize so you cover 20 of the 200 parameters and better on the previous 10 points.
When competition is the hardest, the small details can make a big difference. An additional word in the title. Or that extra qualitative link. Or to allow extra time to optimise site time on page downloads. Therefore, SEO is always a continuous job in most industries that never end.
In early 2015, Google introduced the Rankbrain. An AL computer that learns the search behavior and analyzes all algorithms and constantly optimizes them against how people search and how interests look.
Rankbrain is watching Hummingbird. In Hummingird treated Panda, Penguin, Payday, Pigeon, Pirate, PageRank.
The panda handles the content of the websites. That it is relevant and good content. That the webpage does not have a lot of duplicate content on the pages. Or that the content is thin.
Penguin graduates and reviews the website's link structure. What does anchor text look like? How do the sites look like the links come from. Quality and relevance.
Payday grads how spammy web pages are.
Pigeon counts the local search on web pages. How dominant is your site towards others in your area locally.
Pirate is looking through and grading content / text. Copyrights claim that what is used in content / text is not copied from others.
PageRank looks at how the quality of links around your site looks.
Top Heavy degrades pages with too much advertising and popups.
In addition, Google will premier web pages that are mobile and work in their "Mobile Friendly" index, pages with https and amp pages as well as UX friendly.
Their idea is that if one page is good then visitors stay longer. Other links to your site. It's easy to navigate and find and traffic is increasing. If you are in position 8 and visitors start choosing before those in positions 1 or 4, Google will move you to position as Goolge thinks your site has more traffic with more relevant info and visitors stay longer. Suddenly you have position 3 instead of 8.
In this way, there are more and more basic things on your site that must work optimally to be featured on the first page of Google search results. There is no shortcut. You must look at the site as a whole.