Arguably, keyword selection is the single most important stage in the entire optimization process. If you do not choose the correct keyword phrases you will not maximize your ROI on this campaign. I mention ROI and use it as a reminder that keyword selection is not necessarily about looking for the most searched phrases. A profitable optimization is one which produces the greatest return on investment for the time and money that are available to put towards it.
Bigger Is Not Always Better
If you are a web designer in Seattle who has just started your own business, you could make "web design" the targeted keyword phrase for your site as it certainly has the highest number of searches with 707,962 in September 2009 according to the "Overture Search Term Suggestion Tool". If you have thousands of dollars and many months to dedicated just to attaining those rankings it could be done however, would that be the best use of your time? Alternatively you could target "seattle web site design" with 5,070 searches in September. A Google link check shows the number of links for the top three competitors for the Seattle search had 132, 21, and 47 respectively whereas for "web design" the top three had 18,700, 5,420, and 1,310 incoming links each.
With a good site you would get more work than you could handle with 5,070 searches on Overture alone if you were ranking well on the major search engines. This would clearly provide the highest return on investment for the small business owner who most certainly does not have the time and money available to target "web design" and who wouldn't have the manpower to take advantage of the rankings even if they were attained.
This is an extreme example however it clearly illustrates that sometimes the phrase with the highest number of searches is not necessarily the best target for your business.
Phrases That Sell
Another consideration you will want to make when choosing your keyword phrases is whether or not they are "buy phrases". Phrases with a high number of searches that are not "buy phrases" will tend to bring a lot of traffic, however the conversion ratio will be far lower. Should you choose to target "buy phrases" you may not get the same number of visitors however your ratio of visitors to sales will be much higher.
In this example let's assume you are the marketing director for a well-known accounting company. There will be many choices you can make for your targeted keyword phrase. The top searched phrases in September 2009 that were accounting-related are:
"accounting" with 156,095 searches
"accounting software" with 54,621 searches
"accounting job" with 32,015 searches
"accounting services" with 19,260 searches
"accounting firm" with 13,089 searches
Many might go with their gut instinct and attempt to target "accounting". The problem with this phrase (other than the competition for it) is that the people doing that search are not necessarily even looking for an accounting firm. They may be accounting students, small business owners not interested in hiring an accountant but just looking for tax information, etc. "Accounting software" and "accounting job" are irrelevant, which leaves us with "accounting services" and "accounting firm" as the two main options.
From this point an evaluation of competition should be performed and the pros and cons of making each the primary target should be weighed based on the amount of work it will take to attain the phrase vs. how many searches there are for that phrase.
Often promotions that target multiple "buy phrases" will end up far more successful that those targeting phrases based solely on the number of searches due to the increased conversions and generally decreased competition.
Tools To Use
Armed now with knowledge on how to recognize and choose between different phrases there remains only one question, how do you know which phrases are even searched? Fortunately there are a couple great resources out there to help you find out how many searches are performed for specific phrases. They Are:
The Overture Search Term Suggestion Tool
A decent tool for researching keyword phrases. It indicates which phrases had the highest numbers of searches on Overture during the previous month. The biggest weakness it has, as far as applying it to the natural search engines, is that Overture counts singular and plural as the same and also corrects misspelling so the totals are all lumped together in this tool whereas on the natural engines they are considered differently.
WordTracker is very similar to Overture's Search Term Suggestion Tool except that this tool differentiates between plural and singular searches, does not correct spelling (i.e. it gives the number of searches for misspellings rather than correcting them and giving a total for correct and misspelled words) and gives the results in predicted numbers of searches over all the engines per day rather than just one engine over a month.
They have a great free trial that doesn't give you as many results but which can be very useful.
When using these tools I recommend beginning with the Overture Search term Suggestion Tool and once you've narrowed down your choices, switch to WordTracker to insure that you're getting the right information in regards to tense (singular vs. plural) and also that the numbers match. Sometimes you will find that the numbers are completely different from each tool. In this event you will have to use your best judgment.
Don't forget to check misspellings when using WordTracker!
Tips & Tricks
There are no real "tricks" to uncovering the keywords you should target however there are a few tips. A few pointers that will help you maximize your keyword selection:
Think like a layman. Just because you know your industry terms doesn't mean that everyone does. Don't just think of the words you use to describe your products/services, think of the words you would use if you knew nothing about it other than the fact that you needed it. You may want to recruit a friend and have them run some searches for you.
Think like an expert. On the other side of the coin, there may be phrases used specifically in your industry that people "in the know" would use to search for your products and/or services. Be sure to look into these phrases. You just may find some hidden gems that no one else has thought to target.
Don't target too many phrases. Some SEOs and webmasters target dozens and sometimes even hundreds of phrases. The end result, they often miss the ones they most wanted to attain. Keeping yourself and your keyword list focused will keep your site focused. If your site is focused you'll rank higher for the phrases that will produce the highest return on investment.
Test your phrases. If there is any debate about whether a search phrase is worth targeting it's often a good idea to test the conversions through pay-per-click engines. Set up an account with a PPC engine and bid on the phrases that you would like to target.
You have to remember that the PPC engines do not provide for the same amount of traffic as the natural engines. Test the initial phrases, test alternative phrases, and see which produce the best results. Something else to keep in mind is that PPC are not natural engines. If your ROI is not as high on more costly phrases that doesn't mean they won't produce the higher return on the natural engines where a top ranking does not cost money per click.
In the end you will have confirmed a solid list of keyword phrases and if the PPC campaign is providing a good return on investment you might as well keep it running and enjoy the "bonus" traffic that it provides.