Exploring tkinter and its themed widget set, tkinter.ttk, will take you some time. There's much to learn and play with. Another interesting module to explore, when you'll be familiar with this technology, is tkinter.tix.

The tkinter.tix (Tk Interface Extension) module provides an additional very rich set of widgets. The need for them stems from the fact that the widgets in the standard Tk library are far from complete.

The tkinter.tix library allows us to solve this problem by providing widgets like HList, ComboBox, Control (or SpinBox), and various scrollable widgets. Altogether, there are more than 40 widgets. They allow you to introduce different interaction techniques and paradigms into your applications, thus improving their quality and usability.

The turtle module is an extended reimplementation of the eponymous module from the Python standard distribution up to version Python 2.5. It's a very popular way to introduce children to programming.

It's based on the idea of an imaginary turtle starting at (0, 0) in the Cartesian plane. You can programmatically command the turtle to move forward and backwards, rotate, and so on. and by combining together all the possible moves, all sorts of intricate shapes and images can be drawn.

It's definitely worth checking out, if only to see something different.

After you have explored the vastness of the tkinter realm, I'd suggest you to explore other GUI libraries: wxPython, PyQt, and PyGTK. You may find out one of these works better for you, or it makes easier for you to code the application you need.

I believe that coders can realize their ideas only when they are conscious about what tools they have available. If your toolset is too narrow, your ideas may seem impossible or extremely hard to realize, and they risk remaining exactly what they are, just ideas.

Of course, the technological spectrum today is humongous, so knowing everything is not possible; therefore, when you are about to learn a new technology or a new subject, my suggestion is to grow your knowledge by exploring breadth first.

Investigate several things not too deeply, and then go deep with the one or the few that looked most promising. This way you'll be able to be productive with at least one tool, and when the tool no longer fits your needs, you'll know where to dig deeper, thanks to your previous exploration.

When designing an interface, there are many different things to bear in mind. One of them, which for me is the most important, is the law or principle of least astonishment. It basically states that if in your design a necessary feature has a high astonishing factor, it may be necessary to redesign your application. To give you one example, when you're used to working with Windows, where the buttons to minimize, maximize and close a window are on the top-right corner, it's quite hard to work on Linux, where they are at the top-left corner. You'll find yourself constantly going to the top-right corner only to discover once more that the buttons are on the other side.

If a certain button has become so important in applications that it's now placed in a precise location by designers, please don't innovate. Just follow the convention. Users will only become frustrated when they have to waste time looking for a button that is not where it's supposed to be.

The disregard for this rule is the reason why I cannot work with products like Jira. It takes me minutes to do simple things that should require seconds.

This topic is beyond the scope of an introductory book like this, but I do want to mention it. In a nutshell, a thread of execution is the smallest sequence of programmed instructions that can be managed independently by a scheduler. The reason we have the perception that modern computers can do many things at the same time is not only due to the fact that they have multiple processors. They also subdivide the work in different threads, which are then worked on in sequence. If their lifecycle is sufficiently short, threads can be worked on in one single go, but typically, what happens is that the OS works on a thread for a little time, then switches to another one, then to another one, then back to the first one, and so on. The order in which they are worked on depends on different factors. The end result is that, because computers are extremely fast in doing this switching, we perceive many things happening at the same time.

If you are coding a GUI application that needs to perform a long running operation when a button is clicked, you will see that your application will probably freeze until the operation has been carried out. In order to avoid this, and maintain the application's responsiveness, you may need to run that time-expensive operation in a different thread so that the OS will be able to dedicate a little bit of time to the GUI every now and then, to keep it responsive.

Threads are an advanced topic, especially in Python. Gain a good grasp of the fundamentals first, and then have fun exploring them!