Here are some helpful websites for conducting keyword research:

Wordtracker
One of the first steps to finding the right keywords is to use an online tool like Wordtracker. Like most quality keyword research tools, Wordtracker charges a monthly fee, but it’s highly recommended for anyone serious about keyword research. Check out the wordtracker free trial and use their free keyword research tool to get an understanding of how it works.

Keyword Discovery
One of my favorite keyword research tools is Keyword Discovery. This is the tool highly recommended by SEO guru Bruce Clay. It’s very easy to use, and helps you quickly find daily searches, KEI data, and the number of websites targeting that phrase. I use this on a daily basis, and think you should definitely check it out.

Rushmore’s Advanced Keyword Research Tool
Rushmore is not only the title of one of my favorite movies, but it’s also one of my favorite free online keyword research tools. Amazingly, not many people know this exists, but it’s one of the best free web tools out there. It provides you the daily search stats—like everybody else—but it also gives you the keyword effectiveness index (KEI) score—which most research tools don’t provide for free. The KEI is not precise, but it gives you a pretty good estimate. I highly recommend this if you’re just getting started with keyword research and don’t want to pay a fee.

Overture Inventory
The Overture Keyword Selector tool provides a monthly estimate of keyword searches from Yahoo. This free online tool is okay, but terribly slow. The rumor is that this tool is getting updated, and I hope it does. Some of the data is misleading, so make sure to verify all results with Keyword Discovery or Wordtracker.

Google Adwords
Google Adwords is a tool used by pay-per-click advertisers. It provides great keyword variations on any term you’re trying to target. This free keyword research tool can give you a great selection of synonyms to work with. It will also provide you with keywords you might not have thought of targeting.

SEO Book Keyword Suggestion
No keyword research tool list is complete without mentioning SEO Book’s Keyword Suggestion tool. This amazing tool provides you estimated results for keyword searches in Google, Yahoo, MSN, Wordtracker, Google Trends, and various other tools. The results might not be completely accurate, but they give you a solid estimate for which keywords outperform other terms.

Digital Point
Digital Point is a free keyword research tool that reveals the differences in search queries for both Wordtracker and Overture. I used to use this tool a lot when I first started researching keywords, but now I rarely use it since I rely on Keyword Discovery for this data.

Study Your Competition’s Keyword Anchor Text
If you really want to research keywords, it’s import to spend time analyzing your competition’s websites. Not only do you want to study their keyword densities, but also their anchor text. (Anchor text simply refers to their hyperlinked words). Anchor text tells a search engine more info about your page by what words your using to link out. I use SEO Chat’s Link Analyzer to find anchor text.

Google Trends
Google Trends is a great keyword research tool because it not only shows you the 100 fastest-rising search terms, but it also lets you compare how variations of certain keywords vary. For example, is it better to target “healthcare” or “health care.” Google Trends visually maps out what phrase is more popular. You can also learn the seasons when these terms are used most, and what state/country searches for the term more. This free keyword tool will provide you some tremendous insight.

Study Keyword Densities of Your Competition
One way to find keywords you might not have thought about targeting is by studying your competition’s sites. Use SEO Book’s density analyzer tool to find all the keywords they’re targeting. This can also give you an idea of how often you should be using certain words. I also recommend using SEO Bench, SEO Chat, Google Rankings, and Ranks.nl to research keyword densities.

Good Keywords Free Software
If you’re looking to download some free keyword research software, then Good Keywords is something to consider. This software will help you research results very quickly. It’s actually quite quick, and pretty helpful. It doesn’t give you KEI data, but helpful nonetheless.

Find Synonyms with Go Rank
Once you’ve selected your keywords, it’s always valuable to use synonyms to spice up your content with variations. Most paid keyword research tools like Wordtracker and Keyword Discovery include this service, but Go Rank does this for free. You can also find synonyms in Google by typing your keyword in Google after a tilde. For example: ~keyword