This is coming from a musician that is now about 1 1/2 years into music study. I started by learning about the basic languages and theory of music, and like to just improv (badly, really badly) on the piano. After about 6 months of no progress I spent 1 year learning about 10 songs by ear, 2 of them were on guitar and I transcribed it to piano. These songs all range from difficulty levels of about 4-7 on a 1 to 10 difficulty scale.
After I started taking the diligent and structured approach to learning one song at a time by ear, I suddenly started composing music in my head endlessly. Sometimes I could stop it and control where I want it to go, and other times it naturally flows and I don't bother to edit it as it goes. Sometimes I think about the theory and sounds of all of the songs I learned and I mix around the songs I know in my head. If I hear songs of any variety or genre, my head is always making music along to it. Now here comes the part where I need some guidance in order to ensure that I develop in my ability to improvise and compose in a freely flowing way, as I do in my head, but on an instrument.
I studied Pablo Picasso for a little while when I realized that the only thing stopping me from expressing my own personal flavor of musicality (on any instrument) is years of technical training. Pablo Picasso said that art only flows at its best when all of the technical issues have been resolved by the artist. So my musical anxiety was relieved when I realized that my intuition about my technique needing lots of practice, which was the key to becoming really good, was validated by Pablo Picasso.
So I have to make a decision. In order to maximize my improve/composition repertoire on just the piano, I have been considering just going through the slow process of transcribing what I here in my head into one key (C#) from the simplest melodies and rhythms, to their most complex and technically demanding forms I can imagine, all mixed in with endless and flavorful transitions. I also am dabbling in taking parts of songs that I have learned and putting them into C sharp, and mixing those with my own music, and basically just building up my rhythmic and melodic playing technicality in the key of C sharp for like a year, with the end goal of just being so comfortable with with C sharp and all of the sounds I hear in my head at a moment's notice in my head while sitting at a piano, wherein which I could just musically play for hours without any pauses or interruptions that consist of me thinking about, "Oh where is that sound I'm hearing in my head on the piano, and damn this is a hard pattern to play due to the relation my left and right hand have to have with one another in making the music".
So, based on my own self analysis, progress, vision, do I seem like I am headed in the right direction? Of course my long term goals beyond a year are to be able to learn much more songs difficult and easy by ear and many instruments and to be able to improvise and compose comfortable on all of them in a variety of keys, and record music with all of them.