There is and has always been this speculation that seo's are like all of the snake oil salesmen of the past. Selling their fake bill of goods to unsuspecting victims as the chance arises.
This could not be further from the truth. A search engine is a program and ranks sites as they are programmed to rank them. There are no insider secrets, No one to pay off, and no friends in Google that can do a favor and get your site "special" placement.
A search engine does not wake up on the wrong side of the bed and take it out on your site, it does not prefer one color over the other or even like one design layout compared to another.
The basis for seo is broken down into two separate areas. One is on-page work. This is what you do to any specific page to make it relevant to the targeted phrase or phrases. This causes confusion to many webmasters because you can actually write about a specific subject and completely miss your targeted phrases.
I am sure a mortgage broker could write plenty of content about mortgages without using the word mortgage. This is where many get lost when it comes to on-page work. One of the many factors of on-page work is to have the keyword density at the right level or percentage. If you write the content on the desired keyword or phrase and fail to get that keyword in the content, you have just failed at on-page. This is just one example of the many mistakes of on-page work.
Next is off-page seo, It is the link campaign. Here again you can have the basics and still miss the target. There are many factors that affect links. The main factor with links is the anchor text.
Anchor text is the clickable text with a link to another page or website. The most common mistake with links that I see is that if there is any clickable text, it is usually the company name when it needs to be their keywords. An example of this is that if your website is about frog legs, then the clickable text needs to be frog legs or a phrase with these words in it, Not Billy Bobs website.com.
There are many other factors that affect the effective use of links like the title of the page that the links come from, the position of the links on the page, the content of the page, the pr of the page that the links come from and much more.
There are also many seos that will tell you that reciprocal links do not work anymore. This could not be farther from the truth. They still work fine. The value has been lowered in favor of one way links, but all links still count and have value, at the current trend they will soon say that links have no effect on the search engines. This is also not true.
If you take a look at the internet, it is based entirely on links. You search a keyword and your results are a huge list of links, then, once you choose a link and click that link and read that page you have to click another link to go to another page. If you stop to think about it, you can not navigate the internet without links. So they can not be removed from the algorithms of the search engines.
Consider the road system of the U.S., You can change the speed limits, slippery when wet signs, stop signs and so forth, But you can never remove the roads or the U.S. would cease to exist as the super power that it currently is.
Pure seo is, and will always be based on a basic set of principles just as any other method in this world is. Play by the rules and you will never go wrong. If you are playing football you do not go on the field with a baseball bat! You will get ejected. The search engines are no different. Play by the rules and you will be on your way to a prosperous online business.