https://adwords.google.com/select/KeywordToolExternal

You can do keyword research in Google Adwords via 2 ways:

1. By supplying a descriptive word.

This option will generate a list of keywords relative to your supplied word while in the later case keywords are generated on the basis page content from live site. If you keep the 'show search volume trends' and observe the results closely you can understand how a keyword has performed in each month for past one year.

2. By giving direct URL of your web page.

This option will analyze the input URL and based on the surrounding content it will understand the relevant topics. Based on this information it will suggest many keywords which will be related to that specific page. This feature is really good for no voice users.

This tool provides much additional information regarding keyword which helps you later in finalizing your keyword.

Average search volume:
Indicates the average monthly search volume for the past one year of searches for a particular keyword. Take a better decision for keyword by hovering the mouse pointer on results to see low, average and high search volume indicators.

Search volume trends:
Find out how a keyword has performed for the different months in last one year.

Advertiser competition:
Take a glance at the advertiser competition before you finalize your keyword.