QUOTE: “The score is determined from quantities indicating user actions of seeking out and preferring particular sites and the resources found in particular sites. *****A site quality score for a particular site**** can be determined by computing a ratio of a numerator that represents user interest in the site as reflected in user queries directed to the site and a denominator that represents user interest in the resources found in the site as responses to queries of all kinds The site quality score for a site can be used as a signal to rank resources, or to rank search results that identify resources, that are found in one site relative to resources found in another site.” Navneet Panda, Google, 2015
QUOTE: “You heard right there is no duplicate content penalty… I would avoid talking about duplicate content penalties for spam purposes because then it’s not about duplicate content then it’s about generating in a very often in an automated way content that is not so much duplicated as kind of fast and scraped from multiple places and then potentially probably monetized in some way or another and it just doesn’t serve any purpose other than to gain traffic redirect traffic maybe make some money for the person who created it this is not about content that gets really sort of created for any kind of reason other than just to be there so I person I don’t think about it as duplicate content there is just this disparity it’s the same thing as saying that maybe we created gibberish is some sort of a duplicate content of words but otherwise also exists like I I would really separate those two issues because the things that Aamon led in with URLs generated on WordPress and the things they were going to discuss today later maybe about e-commerce sites and so on I wouldn’t want people to confuse those two.” Andrey Lipattsev, Google 2016
It's important to check that you have a mix of head terms and long-tail terms because it'll give you a keyword strategy that's well balanced with long-term goals and short-term wins. That's because head terms are generally searched more frequently, making them often (not always, but often) much more competitive and harder to rank for than long-tail terms. Think about it: Without even looking up search volume or difficulty, which of the following terms do you think would be harder to rank for?
QUOTE: “The purpose of a page is the reason or reasons why the page was created. Every page on the Internet is created for a purpose, or for multiple purposes. Most pages are created to be helpful for users, thus having a beneficial purpose. Some pages are created merely to make money, with little or no effort to help users. Some pages are even created to cause harm to users. The first step in understanding a page is figuring out its purpose.” Google Search Quality Evaluator Guidelines 2019
Google will select the best title it wants for your search snippet – and it will take that information from multiple sources, NOT just your page title element. A small title is often appended with more information about the domain. Sometimes, if Google is confident in the BRAND name, it will replace it with that (often adding it to the beginning of your title with a colon, or sometimes appending the end of your snippet title with the actual domain address the page belongs to).
QUOTE: “Content which is copied, but changed slightly from the original. This type of copying makes it difficult to find the exact matching original source. Sometimes just a few words are changed, or whole sentences are changed, or a “find and replace” modification is made, where one word is replaced with another throughout the text. These types of changes are deliberately done to make it difficult to find the original source of the content. We call this kind of content “copied with minimal alteration.” Google Search Quality Evaluator Guidelines March 2017
QUOTE: “We expect Ads and SC to be visible. However, some Ads, SC, or interstitial pages (i.e., pages displayed before or after the content you are expecting) make it difficult to use the MC. Pages with Ads, SC, or other features that distract from or interrupt the use of the MC should be given a Low rating.” Google Search Quality Evaluator Guidelines 2019
Ask for a technical and search audit for your site to learn what they think needs to be done, why, and what the expected outcome should be. You'll probably have to pay for this. You will probably have to give them read-only access to your site on Search Console. (At this stage, don't grant them write access.) Your prospective SEO should be able to give you realistic estimates of improvement, and an estimate of the work involved. If they guarantee you that their changes will give you first place in search results, find someone else.