SEO is a science, of making your website rank higher in the SERPs.  There are several factors, which affect your rank.  

 First – the internal site’s structure.  There are many rules that need to be met – otherwise search sites will consider a website amateur/spammy/useless and index it badly ( and in a number of cases might even absolutely drop it from their database ).  

Typically search websites, notably Google, Yahoo or Bing employ crawlers, infrequently also known as automatic robots, to find and index web pages in order to feed their search results.  Nonetheless these crawlers don’t index all of the webpages of an internet site.  They do not index all of the web pages because of various reasons.  The reason they are not able to find may vary widely from straightforward to complicated.  As an example, simple reasons as a broken link may leave a web page un-indexed.  

here is where SEO steps in. They identify why a net page is unindexed and incorporate the obligatory changes. Nonetheless this can attract the crawlers only to a certain amount. In order to ensure indexing, search engine optimisation techniques swear by submission to search websites and directories.  

Sending off a website to search site directories creates links and that in turn enable the crawlers find pages through these links.  These are called  ’backlinks’.  By subscribing for link-building services, one can increase one’s website rating manifold, without flouting the rules of search websites.  In general, search sites trawl the Net, searching for the most natural backlinks from one page to another. If it realizes that a page is deliberately hosting links to a number of other pages, which in turn, are hosting links to this page, the search site dynamically excludes it from its algorithm, and doesn’t rank it at all .  

The above eventuality is a unsophisticated one and given as an illustration. The reality is even though crawlers do index your website ( homepage ), there isn’t any guarantee that it will crawl all of the pages. ( There are many reasons which explain why this happens, but then that is beyond the boundaries of this text ).  

To conclude, do not hesitate to do more research on search engine optimization research.  Remember, there could be one or two details that will make it not as useful as really hiring a professional service for this. But with the proper tools, you will not be far behind.