Straight From The Horse’s Mouth
The best place to go for keyword research is to sign up to Google Adwords and use the Adwords Keyword Planner. It use to be available without an Adwords account but they changed that. Don’t worry you don’t have to actually spend any money on Adwords or hand over your banking details to use it. Google get the majority of searches in the UK and Europe, maybe over 90% of searches. So it is the most reliable source of data.
Other keyword tools like Wordtracker base their data on search engines like Dog Pile and Metacrawler. These search engines aren’t very popular, especially here in the UK and Europe. They also don’t actually know what percentage of the market they occupy so Wordtracker simply multiplies the number of searches on these search engines by 200 and assumes that represents the whole market. They call it an index instead of the actual number of searches.
Once you have created an adwords account login and go to the “Tools” menu and “Keyword Planner”. Select the first option “Search for new keyword and adgroup ideas”.
List all the relevant keywords you can think of.
You may want to use a spreadsheet to come up with your initial list. For instance keeping with the accountant example these may be your initial terms that you then span them out to produce all the different possibilities that make sense:
Paste them in to the Adwords Keyword Planner. Initially it will take you to a tab called “ad group ideas”. This tab is mainly for setting up Google Adwords so for SEO research purposes it is better to click along to the next tab called “keyword ideas”. For my initial keywords it came back and showed me that there were monthly searches for the following: