The first step in a search engine optimization campaign is to choose your keywords or keyphrases for each of your web pages. Keywords are terms that search engine users type in search box to conduct a query. The right keywords are those that: a) clearly describe purpose and content of your site, and, b) allow your site to show up as close to first results page as possible.
A good position doesn't depend only on your choice of keywords. It also depends on how well do you position those keywords in your web page, and how many quality external pages link to you. However, choosing wrong keywords can throw off your entire search engine optimization strategy, so you need to invest a few hours and make sure you do it right.
Let's start with your homepage. Look at it carefully and write down words and phrases that best define your site. Try to form two or three word phrases, since competition for one-word keyphrases is fierce, and it is virtually impossible to get a top position for them. That is why, from now on, we will talk about keyphrases, not keywords.
Once you have developed your list of potential keyphrases you are ready for next step: to analyze demand and supply for those keyphrases, and choose best ones (those with good demand and not enough supply).
We will first check demand for your selected keyphrases. For this, we will go to Overture's Search Term Suggesion Tool:
http://inventory.overture.com/d/searchinventory/suggestion/
Overture is a popular pay-per-click search engine (as we know, pay-per-click search engines are only ones that disclose keyword poplularity for free). You will then type each of keyphrases you selected, and see how many people search for those terms. This tool will show you only those searches conducted in Overture (and only in one month time). However, relative popularity of each search term will be very similar in other search engines as well.
In addition to telling you if your selected keyphrases are popular, this tool will show you other keyphrases that you may not have thought about, which may even be more relevant to your site. For example, if your first keyphrase was "Italian Restaurant", Search Term Suggestion Tool will also display other popular search terms, like: "Gourmet Italian Restaurant", "Northern Italian Restaurant", "Italian Restaurant Pizzeria", "Italian Restaurant Miami", etc. You may also try other keyphrases, for example: "Italian Cuisine", and come up with more specific keyphrases, like: "Fine Italian Cuisine", "Italian Cuisine Miami", "Northern Italian Cuisine", "Italian Cuisine Fine Dining", "Gourmet Italian Cuisine", etc.