#1
I wanted to know how I would go about composing a song? What kind of things are essential to composing songs and solo guitar pieces?
#3
um... form? Structure is a good place to start if you'd like your song to be in a pattern. Solo guitar (bar some classical) has a structure to how the melody and harmony interact throughout the piece. You could go with the above by listening to others to get ideas... but also listen to their song structures.
I hope this helps ya