How do I create Google Adwords test account?

Google does not allow any test accounts. But, you can login to adwords with your gmail email ID, create a campaign, adgroups and ads with relavant keywords for your website for free. But these ads wont be served until you make a minimum payment as mentioned in your adwords account.  Minimum payment differs from country to country.  You get a credit from google if you are a fist time advertiser and transfers the minimum payment for the first time.  You can test your ads live with this initial amount(your transfered amount+google credit).  Do post questions if you need any further clarification.