How are your general programming skills? Are you familar with any programming languages, algorithms, data structures, that kind of thing? If not, then you really need to start from the basics. Otherwise it is just a matter of understanding the UI design. Qt is great since it is easy to acquire and portable, so you can write basic programs to work on the PC with minimal to no work needed to make them work on a mobile device.

If you are past that and are only looking for some tools, have a look at this thread.