Play What You Hear
In this first installment, we are going to introduce the final goal that you are after when you are improvising, which is to play what you hear. Improvisation is not a matter of pasting together a bunch of memorized patterns and ideas, but rather, using the "typewriter " of your choice to play the melody that you are hearing in your head. Remember that you are the instrument and that the guitar, keyboard or whatever you choose to play is only a "typewriter" that you use to express your ideas. Think of it like writing a novel; the ideas for the novel and the words used to express those ideas come from the writer, not the typewriter. The typewriter is only a tool used to put the words on paper. So to, the instrument is the player, not the chosen tool to play the notes.
In order to achieve this end, you must first learn the scales, intervals and arpeggios as well as the theory behind how things work in the world of music, but these are only a means to an end. You learn these things in order to train you ear to hear what happens if you play a specific sequence of notes, so that when you hear a melody, you know where to go to get what you need. Eventually you will "forget" all of this and just play, but you have to have a place to start. So while it may at first be difficult to see why you do this kind of practice, in the end you will achieve your goal of playing what you hear much faster. If you have played something, say a scale in thirds, then if you hear it, because you have played it before, you will know what it is. For example, if I play a major scale, once you locate the first note, then you can duplicate what I did.
By learning to read music, you have the further advantage of being able to read and study what others have done, be they composers or improvisers. Everyone has learned from those who came before, and the more styles and materials that you have access to, the more creative and less restricted you will be in your own playing. Reading music enables you to do this with a wide range of sources. You can then apply anything you learn to any style of music and by doing so, be able to create your own "voice", something that is very hard for most improvisers to do.
So playing what you hear is a process. First you learn your scales, intervals and arpeggios as well as music reading and theory. These are your foundation, so they must be strong. Then you study what others have done with these materials and try to apply them to your own playing. You first learn from others then take that and make it your own. Over time, you will eventually develop the ability to play what you hear which is true improvisation. When you can truly feel the music, then you can really improvise.