The first thing you need to do when you begin chasing a good search engine ranking is decide which words you want to rank well for. This is called performing a keyword analysis.
Keyword analysis involves a bit of research and a good knowledge of your business and the benefits you offer your customers.
There are several websites specifically designed to make keyword analysis easier. Two examples are:

•    Overture’s inventory tool which you can find at
http://inventory.overture.com/d/searchinventory/suggestion/. This tool is free and
very easy to use and understand, but it only tells you how many searches have been conducted in the previous month for your keyword (and similar keywords).

•  WordTracker which you can find at http://www.wordtracker.com. WordTracker is a
much more powerful tool, but you have to pay to use it (you can subscribe for a day for around $10). WordTracker helps you find the most appropriate keyword for your site by telling you what people are really searching for. Here’s how it works… You type in a word which summarizes what you do, and it tells you how many times that word has been searched for in the last month. It also tells you how many other websites
are using that word as a keyword (i.e. targeting the same customers you are). Based on this information, it rates the word. The ‘best’ keywords are the ones that a lot of
people are searching for but which few websites are targeting. WordTracker even
suggests and rates alternative related words.

TIP: When you’re using WordTracker, bear in mind that it’s just talking about
numbers, and numbers don’t always tell the whole story. So don’t just jump in and
use the best rated keywords; you need to consider your own situation. It may be the case that you’re forced to select a keyword phrase which is not rated particularly
highly. There are two situations in which this might happen:

i.    You’re in a niche market with relatively few customers searching for the keyword. In
this situation, you’ll probably find it relatively easy to reach the top of the rankings,
but you won’t generate a huge volume of traffic when you get there.

ii.     A lot of your competitors are targeting your keyword (it’s hotly contested) but it’s the
only one you can use. If you target it, you’ll just have to work a bit harder on your
backlinks in order to rank highly. When there’s a lot of competition for a keyword, it’s likely that the traffic payoff is good once you reach top.