Where to begin to start making real applications?

[FourSight]

I'm kinda lost on where to begin. I know most of the main features of C++, such as Classes, Functions, Arrays, etc, and have also done some games with Allegro game library. I want to start making real applications, something like a music player that plays .mp3 files, a chat program similar to MSN but with alot less features, etc.


Where do I begin? Any advice is appreciated!