Really, if you aren't sure how to improve your CTR, I would:
* write AdWords support using the Contact Us' link in your account, and ask for specific suggestions, based on a review of your account
* Keep reading here on WebmasterWorld, every day - and soon you will be quite expert
* Use the resources available to you from the Help link at the top right of every page of your AdWords account. For example, here is just one link from that resource that you may find useful. There are many others:
Optimization Tips:
[adwords.google.com...]
* Experiment - by making informed decisions, and then monitoring the results
PS - I've just responded to another one of your posts with other tips that should help you increase your CTR, by using targeted Ad Groups.
AWA