I increased my CTR in Google Adwords by more than 2% with a single change in my account.

I simply deactivated the option that my ads are shown on parking pages provided by sedo.com, parked.com or similar services and on error pages.

You can find this option in your adwords account under “Site and Category Exclusion Tool” :

If you are running any Google Adwords campaign you should take a look on this setting.