How do you write music?

Follow the way that Goldenavatar described. The most innovative prog band perhaps was Gentle Giant, and its leader Kerry Minnear had a degree in composition.

So try taking musical classes, and on the other hand, study great literature and art - it is easier to create great form if it has some idea about it - especially transforming some recurring themes, representing that ideas, which also was way of composing great progressive songs.

Do not listen to these wierdos who say there is no formula for writing music, they clearly don't know much about music. There are MOST CERTAINLY RULES! Did Bach just sit down and totally make crap up? Well he probably did, but it was a very formulaic approach. Why do you think there are different genres and styles of music? The reason is because there are different rules and formulas for each one. There ARE rules for blues. There ARE rules for Baroque. There ARE rules for Jazz. Anyone who claims that music is obtained by just doing whatever the hell you want is musically illiterate. They may be able to come up with some interesting stuff occassionally but that will be the exception. So if you want to learn to write some music you just need to learn the rules of the style you want to write.

I personally would suggest, if you have not done so, take some college level music theory classes. That helped me tremendously. One thing you will learn is tonal harmony from a classical perspective. Since prog artists are often influenced by classical forms, this would be very beneficial. You have to learn to walk before you can run. Learning the basics of tonal harmony will help when you get to the point when you want to start breaking the rules. You can't break the rules if you don't know the rules. Plus, once you know the rules for writing a 4 voice chorale in the style of Bach, anything you write will sound good. I'm not kidding. 4 voice chorales will then lead to keyboard pieces and then on to your own instruments. When I was taking music theory I would write chorales and have no idea what they would sound like (I have not taken an ear training course yet). Then when I heard them I was always amazed that they sounded so pleasing. All because I followed the rules

One thing I've found in my own experience is that it's much easier for me to write starting with a harmonic basis for the song. When I was a bit more inexperienced I always thought you just come up with a melody in your head and then add to it. That has proven to be much more difficult for me. Now I try to come up with a chordal model first and then add to that.

Also, my teachers always say, "Don't try and be creative," when you are first starting out. Start off doing the very cliche stuff. This will give you a firmer grasp on how harmony works. Plus most works are NOT very complicated harmonically. That includes prog. Most tunes follow very standard harmonic progressions. For example pretty much every jazz tune in the world is based on ii-V7-I chord progressions. Sure there are more things going on, but those are usually ornamental things, not the basis for the work.

Chew on that!

I write it using my language: Música. Your Question is very valid, but weird. There is not a way to create something by just following a method. I know that many movies are made using somekind of "template" that works almost al time, but nobody can create a movie like "8 1/2" by following some kind of "instruction's package". You must concentrate, find out if you can do it, and then use method to put some order on your ideas. But if the problem is the idea, I'm sorry, but you are lost. at least until the idea finally reveales to you.

The Lost Chord wrote: I play instruments all day, i am an avid flute, piano and guitar player and i have been playing piano for my whole life and i know music like i know math! But i cannot seem to create epic melodies, I can write songs easily, but i am never satisified with what comes out at the end...is there a formula people follow?  How is it these people made such great music back in the 70's and 60's, what was it about them!?!

Lord Qwerty's Advice on Art:

There are three factors in art. Time, technique, and talent. To create great art, you require at least two of them. Time alone yields a waste of time. Technique alone yields boredom. Talent alone yields slop. All three strung together yields genius.

Time is by far the easiest asset to acquire. You need to find yourself an area where you feel at piece and can roam through chords and notes at your leisure.

Technique is the middle sibiling of the three great assets of art. More impressive than time, but not as inspiring as talent. This requires patience to gain, though. The most skilled musicians take years to reach their peak. Practice, practice, practice... but too much practice can stifle your creative prowess through rigorous conditioning.

Talent is by far the most elusive facet of artistry. You don't obtain it per se. It's not necessarily ingrown, but not everyone has access to it at will. There are a few theories on how to gain it. The first and most difficult is to have a tragic event in your life. This will spur your conscience and imagination to create alternative landscapes so that you may avoid reality. Alas, not everyone is so lucky to lose their father in war or be abused as a child. Therefore, it is more feasible for some people to simply take as many drugs as possible.

I hear the music inside my head and then i try to play it on a instrument