How do I start making my own UI?

Greetings everyone, I have been using blender for about 2 years now and I have grown somewhat accustomed to blenders interface however I have seen threads and links for downloading/installing custom themes but how do I go about making my own? Any help is appreciated thanks! :smiley:

To change the interface with python see

For the interface appearance see the File / User Preferences / Themes panel

Thank you.