How to recognize a Google penalty 
With this list of points that will result in a Google Penalty, you can easily verify that your website has committed these facts. Detecting a Google penalty is pretty easy this way. You can also find solutions here to cancel the penalty.
1. Spammy domain
Watch out with buying domains from others, as you do not know how they dealt with them. If a domain has had a very spammy link, or has had other types of penalties from Google, this is a bad thing for your business. Via Webmaster Tools you can indicate to Google that you want to make a fresh start with this domain.
2. Black hat SEO
Everything that falls under prohibited techniques is the worst thing in terms of penalties, trying to cheat the search engines with cloaking, hidden links, hidden text, doorway pages, link farm links and so on.
3. Buying links
Buying links is something Google doesn't like. You are probably not the only one who has purchased a link on such a website, and such a site may display a pattern that makes it clear to Google that links are being traded. Since anyone could buy links for their competition to attack their site, it is difficult for Google to deal with this, but if you have too many of these links you will certainly get a penalty.
4. Duplicate content
Always write unique articles for your website and ensure through .htaccess re-directs that there is also no duplicate content within your own site. You can control on Copyscape.com whether your content is unique, and whether someone else has copied your texts. In the case of duplicate content, only your page will receive a Google penalty, unless the entire website is full of it.
5. Reciprocal links (back and forth)
If you agree with the owner of another website that he links to you, and you link to him, these are reciprocal links. This type of link behavior can lead to a penalty, especially if your website has several such links. Never link to a website that links to your site. If you have multiple websites and the other side too, you can link to each other by doing this through completely different sites, but watch out.
6. More than 1 hyphen (dash) in the domain name
Google no longer likes the domain names that have too many dashes in it, if your domain has it, then consider buying a new domain, putting your website on it, and redirecting the old domain via a joker 301 re- directly to the new website.
7. Foreign links
Make sure you have pages in multiple languages on your website so that people can link to them. Linking Russian or Japanese pages to your Dutch website makes the situation very suspicious for Google. Since everyone in the Netherlands speaks English, I think you can link to English-language websites, at least Google should understand that we understand this language well.
8. Too many keywords
Write your texts in such a way that 6 to 20% keywords appear on the pages, but more importantly that the texts are legible and not intentionally crammed with keywords, this will certainly be penalized otherwise.
9. Footer and Sidebar links
These places on your website are known to Google as the place par excellence where purchased links are placed and looks very unnatural. Make sure that links are in your content of the page and make sense, do not link to things that fall outside the story of course.
10. Lack of niche links
Why would a website for medical science link to a website for new cars? Certainly if there are many such links on your website, this is very suspicious and results in a penalty. Always try to link in a way that makes sense and fits within your sector.
11. Anchor text of incoming links
If too large a percentage of the links that link to your homepage, for example, have the same anchor text, this is strange, no more than 15 to 20% of the links may have your keywords. Make sure that the majority of links have anchor texts such as "yourdomain.com" "Your domain" "click here" and other meaningless words that are usually used in a normal link pattern, as long as you can check this yourself.
12. Neglected sitemap
Google uses your sitemap that is offered through Google Webmaster Tools, make sure it stays a bit up to date and that Google does not think that this will be neglected. Here you can quickly create and download your sitemap.
13. Bad inbound links
If other sites link to your website and the pages do not exist, the sea and 404 error page will be displayed. Of course your page will be removed from the SERP by Google if this is the case. If the entire site is neglected, the website will receive a penalty. Via Google Webmaster tools you can detect crawl errors and redirect them via 301 in .htaccess or have these URLs de-indexed via robots.txt.
14. Bad outbound links
The website you link to is subject to change, so you might link to pages that no longer exist. If this is common on your website, this indicates negligence for Google and is penalized. Check your website once in a while with a program like Linkchecker and correct everything.
15. Site-wide links
The same link that returns on every page, as a web designer it was customary to put your link in the footer, nowadays this provides a penalty for the way in which purchased links are placed on sites. It is better to remove them, especially if the websites are not really related (niche).
16. Sponsor links
Having sponsors is of course good for you, but watch out that you do not link to entire series of websites. If linking is required, make sure that these links have nofollow tags.
17. Duplicate content by language
For example, if you have the same page for a Dutch and a Flemish audience in which the majority of the text is the same, this is also considered as duplicate content, unless you indicate this to Google via the meta tags on the page.
18. Affiliate links
If advertisements predominate on a page, and certainly if there is little and bad content on it, there is certainly a reason for a penalty. The public is not interested in such a website, so neither is Google. Limits the number of advertisements.
19. An excess of H tags
Google likes to see the H1 and H2 tags to know what's important on your website, but preferably use only 1x H1 on a page and a number of H2s. Too many H1 tags certainly ensure a penalty for the page.
20. Too long titles, too many keywords
Don't stuff your titles completely, the optimum length at the moment is 65 characters, so no titles with lengthy sentences with your keywords in it, only use the strongest keywords for it in a powerful sentence. The same applies to meta keywords: enter 2 to 5 combinations, not an entire laundry list.
21. Slow website
If no attention is paid to optimizing images, cache, compressing files, etc., a website can sometimes load very slowly, visitors will leave within 30 seconds and the bounce rate of your pages will rise sharply, resulting in a penalty. Always use a good theme and preferably put your website on CDN to keep it fast.
22. Lots of downtime
If your website is on a server that cannot be reached for a long time due to any cause. If your website is not accessible, then Google naturally does not want to send anyone there either.
23. Polluted comments
Certainly with Wordpress sites you have to make sure that the comments like these are on and are published in this way are not full of spammy links and bad texts. This is very annoying and also bad for your website because Google does not understand this. Preferably remove the option to leave comments on your website or keep a close eye on it.
24. Hacked website
If your website is hacked this should be resolved within a day or 3, if you just leave it at that time the IP of the server will be blacklisted and this has a very negative effect on all websites on that IP, apart from the fact that this has many more harmful effects.
25. Link to suspicious sites
Never link to gambling websites, adult sites or sites that sell adult products, sites that carry out illegal activities, and any other website that you yourself think is based on all the rules here in this article that Google may have a problem with this could have a website.
26. SEO marketers
If you have SEO campaigns run make sure that these people use legal techniques, talk everything through so that you know what exactly is being done. You do not benefit from rising quickly in the SERP and then falling like a brick after paying for the services. iPower is a very professional SEO company.
27. Spun texts
Watch out with copywriters, if an article is not written by hand but an existing text spun with a program, this is for Google duplicate content, but also trying to bottle the case is a serious offense. Write your texts yourself or leave it to reliable people and ask again to be sure.
28. Landing pages
It used to be good to have many different websites, and to link them to your most important website. Nowadays this results in more penalty points. Try to draw your attention to 1 good website. If, for certain reasons, you change your domain name, it is best to redirect that old domain name to the new one with a 301 and not let it exist and to link to the new website from there.
29. Too many outbound links
Linking too much to all sorts of websites can give you the idea that you get money for this and result in a penalty. If you do not receive a penalty, it is still the case that all these websites receive linkjuice and your Pagerank will fall as a result of which you will also be found worse.
A 301 redirect can cause a penalty to be skipped from one domain name to the other. So watch out with redirects, make sure that there is no question of penalties for the domain being redirected.
31. Competitor attack
In the past, a website was never held liable for links that link to the site, since you cannot control this yourself. Google has abandoned this and will give a penalty for suspicious link patterns. Your competitor could therefore intentionally provide faulty links to your website so that it is penalized. Go to Google Webmaster tools and check all backlinks to your website, and "disavow" these links, or tell Google that you want nothing to do with this, not in a good and not in a bad sense.
32. Few outgoing links
Not linking to other websites at all is not a good idea, try to keep your website as natural as possible, and link here and there to other websites, both follow and nofollow.