There are 6 major and quite common issues that can make SEO even harder and more difficult than it is.

1. There is adifference between on-page SEO and off-page SEO

Those factors that can be entirely influenced and completely optimized by you are falling in two broad categories: on-page factors that are determined by directly looking at the page you try to optimize (keywords, written content, page architecture, navigational structure, etc) and off-page variables which are not entirely in your hands, but depend on other external websites (for example, links to your website from other sources, social networks, etc).

The on-page factors can be easily tweaked and modified along the way and that’s a great plus. On the other hand, they can only be optimized to a certain point. Once you have fulfilled the requirements your job is done.

The off-page factors are more difficult to control, but they often have a bigger impact on your search engine rankings than other on-page factors. Why? Because they are harder to manipulate and the third-party endorsements are extremely important for search engines. More than that, they can always be improved. There is always room for more social shares or more inbound links.

Obviously, we are talking about two different approaches and SEO strategies and if you want to learn how to SEO a website, if you want to transform Google and Bing into your slaves, you will need them both. This is the primary reason why SEO is difficult and time intensive.

2. Crawling and indexing problems

We have already touched briefly on the topic of crawlability. As I said, there are many different web elements, technical solutions or coding practices that can prevent spiders from crawling, “translating” and indexing your website. Images, videos, frames, Flash animations, Javascript snippets, broken links or poor link structures, password protected pages or directories, online forms, duplicate pages, missing or corrupted sitemaps, robot.txt errors, audio files, plugins, dynamic parameters, wrong redirects, hosting issues etc.

Unfortunately, the list is quite long and every single element or piece of content which cannot be seen, read, interpreted or followed by crawlers is a genuine risk factor that will harm your visibility in the search engines.

The good news: these problems can be easily avoided or solved using free spider simulators, sitemap generators, link checkers, etc.

3. Different and constantly changing algorithms

As you probably know, different search engines give different results for the very same search query or search string. Each search engine has its own – quite different – algorithm. These algorithms are based on more or less identical ranking factors, but they are weighted differently. In other words, each algorithm can – and probably will – assign a completely different weight or value to the very same ranking factor.

And obviously, the very first step is to submit your site to multiple search engines. At least to Google, Yahoo and Bing!

More than that, these algorithms are constantly refined in order to provide better, more relevant and more popular results. While most of these changes are minor, occasionally search engines may roll out major algorithmic updates causing fundamental changes and dramatic shifts in the whole SEO industry. When Google launched the Panda update in February 2011, thousands of “shady” websites disappeared from the radar overnight. The Panda update – aimed to lower the rank of “low-quality” sites – reportedly affected the rankings of almost 12% of all search results!

The bottom line: in the world of search, change is constant and you have no other choice but to evolve together with the search engines.

Is highly recommended to follow the Google algorithm changes. You can easily do it here:

https://moz.com/google-algorithm-change

4. The competitive nature of search engines

I won’t lie to you … There’s a cutthroat competition! The average search results page contains only ten positions and the first three positions will receive much more traffic than other results down the page. With so much exposure and attention going to so few listings you need to achieve more than just being the best of the rest … And obviously, you won’t become the best by being like the rest!

The good news: you don’t need millions of hits to capture your customer’s attention. The key is to know and to understand your target audience. If you can create valuable content in order to provide a relevant answer to a given question or a reliable solution to a specific problem, you have already won. All you have to do, is to find a few well-targeted keywords that can generate at least 100 searches per month. That’s a considerable amount of traffic and more importantly, it means less competition. Optimize efficiently the given web page using those keywords and believe me, sooner or later you’ll be there on the first page of the search results.

5. Problems matching queries to content

Nowadays the search engines are incredibly smart, but they are still just … machines. They are extremely efficient robots performing tasks that are defined by humans. The problem: they are trying to answer a question phrased in a certain way by a given person (the person who is performing the search) using instructions which have been defined by other people (developers) and querying databases that have been created using a mind-blowing amount of data provided by several other people (website owners, SEO experts, etc).

To put it simply: the search engines are trying to provide the most relevant answer to a given question, but any question can be phrased in many different ways and even the slightest difference will produce a completely different search results page. Every single synonym, uncommon term (for example, blood glucose instead of blood sugar), grammatical error, language-subtlety (for example, flavour instead of flavor), singular or plural form, etc can work against you … or in your favor.

The good news: everybody is affected. The golden rule: check what people are searching for, and try to use as many exact matches as you can in your content.

6. There is SEO and paid SEM

Sometimes these two terms are used even as synonyms ... which is wrong!

SEO involves all the on-page and off-page optimization efforts made to achieve better rankings in the organic search results. In this sense or context search engine optimization is a free marketing method based on various optimization techniques. It’s an essential and compulsory marketing method. No matter what are you doing online, and no matter how big or small your company is, you are going to need it if you want to survive.

SEM or search marketing basically is the paid version of SEO, meaning almost everything you pay for to get more search traffic. It’s a marketing method that involves the promotion of a website by increasing its visibility in SERPs primarily through paid advertising (for example, PPC ads). In other words: SEM is an alternative marketing method. If you have the needed budget you can use it to conquer keywords that are highly competitive for organic results, to get a great amount of traffic in a short period of time, to test the converting power of given keywords, etc.

The "problem"? SEO and SEM are complementary marketing methods. Each one has strengths and weaknesses, and you should use them both. According to Search Engine Land …

Marketers using both organic SEO and PPC ads see an average of 25% more clicks and 27% more profits compared to using a single technique.

The key is to find the perfect combination.