To improve the performance of your AdWord campaigns and groups, and more easily manage your AdWords account, you should:
Monitor the overall Campaign Summary window for performance daily.
Monitor the summary window for each active campaign daily.
Monitor the summary window for each active Ad Group daily.
Understand the meaning and implications of Ad Group performance.
Learn to use the Ads Diagnostic Tool to see if your ads will run against specific search queries.
Optimize ads using the Keywords Tool and the Traffic Estimator.
Learn to use the tools available for modifying ads, keywords, and settings on an accountwide basis.