It is not enough to create strong calls to action on your website. If the user doesn’t understand the benefits of completing that call to action they will ignore it.
Before you call a user to action, first clearly describe what they will receive in return.
Take Skype for example. Skype has a very clear call to action on its homepage (download). However, that action is associated with a strong reason to do so.
Look at your own website and ask yourself whether the benefits of completing a call to action are obvious.