Many organizations make the mistake of thinking that once created, their AdWords account should be left to work on its own. "However, it's fundamental that you monitor the results that the account is generating for you so that you can adapt it as frequently as it's necessary. Don't base your decisions for introducing change on the amount of clicks that your ads obtain, but rather take a look at the number of conversions that you're getting," stated Google.
"Let your new campaign run for some time so that it generates significant data for you to evaluate and so that its performance stabilizes. After 4 - 6 weeks, monitor the results you've obtained from your ads and keywords. Use this information to optimize your account and improve your keywords like shown in the video below. Decrease the CPC of the bad performing keywords, increase it for the keywords working well and delete those not generating valuable traffic."
"Do you've a list of negative keywords? Review and add to it. Else, analyze what words are triggering your ads and include those that're not related to your organization as negative keywords.
It's also recommend evaluating your ad text regularly. Add variations similar to ads that're working well, modify the ads that're performing less well and delete the poorly performing ads.
After introducing and saving the changes, let the campaign run for a reasonable amount of time and review the results again! Molding your campaign is a constant activity and can help you meet your campaign goals," Google explains.
For more information on optimizing your campaigns please check out the AdWords Optimization Center.
More Info: AdWords Optimization Center