Balsamiq is a great tool, but it is just that. Learning about customer experience, user experience and interface design takes time, dedication, great interest, and a passion for delivering simple yet intuitive designs that people respond to. You need not only know what you are doing, but also be able to answer why you are doing it.
To that point, I now want to share with you some great resources, both in print and online, that will help you get to that next level.
The list that follows is by no means complete or exhaustive. It is merely a starting point. You will find that each book offers great insight into the world of user experience, design, and the psychology around it. As you will see, there are quite a few to choose from. Pick one and start reading. When you are finished, pick another and read that one too. There is no hurry. Just enjoy the process. I do have to warn you though, once you start delving deeper into the world of user experience and design, you may...