Google sanctions
To date subject of sanctions by the Google company is particularly relevant. Daily webmasters received, receive, and will receive notifications from the Internet giant's about the detection of incorrect SEO practice. Analysts have tried to bring together all the reasons why you can "fall from grace" to Google. There had accumulated 25 reasons.
1. Cheap links. If you decide to buy 10,000 links for 10 $, be prepared to get a negative reaction of Google. Advertising on Fiverr and similar resources, mildly speaking, is not welcome.
2. Link exchange. Link exchange under the agreement between sites has long tracked by the search engine and leads to serious consequences.
3. Links which transmit PageRank. Buying links to advertising is not banned, but make sure once again that you have marked them as paid. Otherwise you break the rules for webmasters installed by Google.
4. Hiding of the links in Javascript, CSS, etc. The evolution of search engines is not standing in one place, and that, which before was possible to hide in the additional files, is now easily recognized by the system.
5. Very rapid links growth. Appearance of too many links to your site in a short time - is a sign of frauds with search results. In order not to fall under Google sanction, you should attract natural links or else focus on the purchase of fewer links, but of better quality.
6. Low anchor text distribution. When you creating links, try to use in their anchor text as much keywords as possible. Otherwise, the search engine will have to apply to you sanctions.
7. Links from blogging networks. Most of the blogging networks already "are impaired" by Google. Try to avoid their links.
8. 
It's better to avoid links from the content, from which the readers can take no good for themselves, especially in case of foreign resources.
9. Cross- links. According to Google, this is nothing more than an attempt to manipulate search engine. Try to get more valuable links to your website.
10. Broken links. From time to time, try to check the links on your website. A large number of broken links, and as a result, a small number of clicks on them, certainly will not have a positive impact on your position in SERP.
11. Links to questionable websites. Link to the website with the "original" content (gambling, resources for adults) also will not add the rating for you, believe me.
12. Reoptimization. Optimizing of your site - is good deal. However, it is important to not "overplay". Using on each page of the portal of all known to mankind SEO methods is not recommended. Google looks at this as on attempt to manipulate the SERP ratings.
13. Website drop. The user is always right, so if your website is not working for a long time, then Google has the right to impose on you certain sanctions for that.
14. "Indigestible" content. Do not take the wrong path in pursuit of speed of filling your website with information. Low quality material which was gathered by the special programs for a quick hand, is not intended for normal human perception. And since it is not for the people, then it is treated as spam, by the search engine. Remember that!
15. Low quality content. As Google has many times declared - priority is given to sites with information of a good level. At this stage, you will not be punished for this, but be sure that they will learn how to do this in the future. It's better to be safe.
16. Borrowed or duplicate content. Of course, no one will punish you for the duplicated material just like that. But the system can do this in a different way: to filter all of your pages in the search, so that the source material was in the first place.
17. Keywords. Do not try to cram all the keywords in one tag. Google do not like this.
18. The abundance of advertising. This is not good when you inserting a lot of advertising on your website. It will be good enough to remove it at least from the top.
19. Doorways. You will not escape punishment, so it's best to give up this kind of search engine spam.
20. Cloaking. The use of cloaking contradicts the simple Google rule: all the pages of your site should be opened to search.
21. Applying of H1 tags. In order to increase the positive effects, some webmasters are trying to fit a few titles on every page. Cheating is quickly recognized by search engines and is punished.
22. Hacked websites. If the signs of breaking by hackers will be found on your website, it will automatically fall into the black list of Google, and therefore completely excluded from the SERP.
23. Abuse of automated requests. Using of "illegal" query tool contradicts the rules for webmasters. Google is not often punishing for this, but still is not worth risking.
24. Hidden content. Do not try to deceive search engines by inserting additional content, disguised under the background of your website. The detection of this - is only a matter of time, but it will be very hard for you to avoid the sanctions.
25. Black methods of promotion. Google often finds portals, which boast on left and right about that they have discovered under-the-table way of effective promotion. If you really were able to find a new effective SEO method, then at least keep it to yourself.
