Comparing your Google Analytics data side by side with the dates of official algorithm updates is useful in diagnosing a site health issue or traffic drop. In the above example, a new client thought it was a switch to HTTPS and server downtime that caused the drop when it was actually the May 6, 2015, Google Quality Algorithm (originally called Phantom 2 in some circles) that caused the sudden drop in organic traffic – and the problem was probably compounded by unnatural linking practices. (This client did eventually receive a penalty for unnatural links when they ignored our advice to clean up).
The goal of successful SEO is to obtain a high-ranking placement in the search results page of a search engine (e.g. Google, Bing, Yahoo and other search engines). Internet users often do not click through pages and pages of search results, so where a site ranks in a search results page is essential for directing more traffic toward the site. The higher a website naturally ranks in organic results of a search, the greater the chance that that site will be visited by a user.
Understand and accept why Google ranks your competition above you – they are either: more relevant and more popular, more relevant and more reputable, better user experience or manipulating backlinks better than you. Understand that everyone at the top of Google falls into those categories and formulate your own strategy to compete – relying on Google to take action on your behalf is VERY probably not going to happen.

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.
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.