Understanding the world of search engine optimization, or SEO, can be hard if you are new to the field. There are a lot of strategies out there that can help you to increase your rankings; then again, there are also a lot of people who will give you bad advice. Which advice should you heed, and which should you avoid? It can get murky. Don’t be shocked if some of the do’s and don’ts seem very similar. Bad SEO advice thrives by looking like good advice.

In general, creating outbound links from your site to another site is a very good thing in the world of SEO. The quality of the sites that you link to, however, can make a big difference in the effect that it brings you. If you choose to link to sites that fall into the categories below, then you can end up reversing all of your work thus far — or at the very least, not helping your rankings.

1. Sites that have been categorized as a bad neighborhood by a search engine. These are sites that have been penalized for over linking — for using links inappropriately. How do you spot one of these sites before you link? The simplest way is to search for the domain name (not the URL) in an engine. If it does not show up, it has been blacklisted. You may want to try this with a few engines.

2. Adult sites. Aside from the fact that you may offend your readers and lose them, you run the risk of getting your site moved into that category if you have too many links to this type of site. There is no magic number here, where you can link to the sites and get jumped. Each search engine’s formula works differently. Just be aware that you need to have less of these to fall into that category if you have more related keywords on your site. This means that unless your site is truly meant for adults only, you need to be very cautious with these links.

3. Black holes. This is a term for sites that get links without giving them in return. Sure, it will not really damage your SEO, but it does not get you anything. Be wary of sites with no outbounds, or only “no follow” outbound links. One of the biggest in that category is Twitter, which does all links as no follow, as well as some major news sites. Yes, Twitter has a lot of great uses, but SEO is not one of them.

What about inbound links? Don’t they matter?

Yes, they do. You can’t do anything about it if one of the sites in this category chooses to link to you. If, however, you do not link to them, you can steer clear of one of the biggest problems possible, the reciprocal link. These links count heavy in a lot of formulas, and having them link to the wrong sites will drag you down.

Another potentially bad strategy is using a paid link service or link trade site to get links for your site. Using a paid link or a link trade service can get you into one of the situations above. Most owners of decent and reputable sites prefer to get their links in other ways. So, be aware that these communities often have at least a few of the sites that fall into those unfavorable categories.

Read more of Katie Gatto’s guide.