As with anything, it takes time to learn a programming language well enough to be competent with it. It also takes a bit of dedication - reading books/tutorials/documentation, asking questions, writing programs, making mistakes, and most importantly - learning from them!
When it comes to learning your first programming language, alongside the basic syntax of the language, you also need to learn some other fundamental skills that are language independent. Things like learning how to think algorithmically and break problems down into smaller, logical chunks; using procedural and/or object oriented program design; design patterns; data structures; debugging skills etc. Once you have these fundamental skills nailed, learning to program in other programming languages simply becomes a case of learning the syntax of the language and any other language specific quirks/oddities - at least, for the most part anyway!
WRT learning Python, find a good book or tutorial that goes right from the beginning and teaches the fundamentals of programming (see the transferable skills listed above).
Once you feel that you have a good grasp of program design and you are comfortable designing programs and implementing them in Python code, the next step is to start looking into some of the (many) 3rd party GUI libraries that have Python bindings (tkinter, QT, wxWidgets etc), or perhaps a game engine like pygame or SFML (Small Fast Media Library); And start writing some graphical/desktop applications.
Don't try to learn all of these frameworks at once, just pick one or two to focus on. Most Python libraries have really good documentation, including tutorials and example applications that you can study and learn from. There are also a wealth of ebooks available online (both free and commercial) - that cover using various libraries in Python.
When it comes to learning how to use any 3rd party library/module, searching for documentation, tutorials and/or code examples is just about all you need to do before plugging it into your code.
Once you are comfortable designing/implementing GUI code and using other 3rd party libraries/modules in Python, you're pretty much there - you've pretty much mastered the language!