1. Google Keyword Planner
Okay, this one is pretty boring and widely covered, but let's face it. Google has a monopoly on search engine traffic so no good keyword research project would be complete without first using Google's Keyword Planner.
Google's Keyword Planner is pretty straight forward. You put in the URL to your webpage or you give a few keywords you think people might use to find your products or services and it spits out some suggested keywords you may or may not have already considered.
To use the Google Keyword Planner you have to sign up for a Google account, which you already have. So that's not going to be a big deal. The Keyword Planner is tightly integrated with Adwords so Google can make it convenient to spend your money on their PPC platform.
2. Google Trends
You probably knew about Google's Keyword Planner but maybe you didn't know about Trends. Google Trends show you how different keywords are trending. You can even compare keywords against each other. I've had this tool come in handy for me when I was spending a lot of time optimizing for a keyword, only to find out there was another that was more attainable and generated a heck of a lot more searches.
One neat feature of Google Trends is the inclusion of Youtube searches. Youtube is the second biggest search engine and is a great place to get traffic. Knowing which terms people are searching for on Youtube gives some extra insight, especially if you're doing video marketing.
3. KeywordTool.io
Keywordtool.io is a great research tool if you're looking to expand your horizons beyond Google. Keywordtool.io will give you some good data for free, but some great data if you upgrade to one of their paid plans. This includes data from multiple sources that aren't Google such as the App Store, Bing, and Twitter.
4. SEMRush.com
SEMRush is another keyword research tool that charges fees. However those fees may be worth it to get insight on not only the keywords people are using to find sites like yours, but even which keywords your competitors are targeting.
I've used both the free and the paid version of SEMRush and found the data to be more reliable than most other keyword research tool. I find it particularly helpful in determining whether I'm winning or losing the battle on specific keywords.
5. KWFinder.com
KWFinder.com is a lot like SEMRush but with a cleaner interface. Like nearly all services that aren't Google they provide certain features for free and then if you want to get into the nitty gritty you gotta pay to play.
Whatever the case you can get plenty of good information by using the free tools provided by KWfinder.com. Simply pop in the keyword or phrase you'd like to analyze and it will spit out all kinds of helpful data including things like how many times the specific word or phrase is searched for every month.
Maybe you've had experience using other tools to find keywords to target with your SEO campaigns. If you know of some other good tools or just want to share be sure to leave a comment below.