I've noticed of late that I have a tendency not to stay in a key signature unless I want to keep a section of a song more accessible to lay listeners. I think this relates to how I enjoy music, in that I enjoy scripted interludes and bridges more than solos. For solos, keeping a consistent scale is very useful.

By example, one of the first songs I ever wrote on piano started with a D major triad root position, slipped up a half step to a Ab 2nd inversion and back followed by a little melody in Bb major and then stepped into C mixolydian. The first two chords come from scales with almost as little in common as possible. Since then I have learned more about extensions and alterations, which can only make it weirder.

I also realized what makes jazz music often feel too safe to me. As many people focus on complex chordal elements, they keep rhythm, tempo and dynamics simple. These other parts help me feel a purpose to the music and they are frequently absent. I expect many people to speak to some jazz music that has complex rhythms, and I concede this point, although I don't find it to be extremely common place.

Knowing that my approach is not common place, I wondered what other people liked about music and how it influenced their compositional styles. Speak up. Let us know what drives your writing and what is signature to your compositions.

Key of Fmi can have aforementioned Ab Bb C and D (although Db would be more in line)
F dorian= F G Ab Bb C D Eb
Chord qualities would need a little poetic license.
Not outlining traditional key centers is cool but we can almost always justify the seemingly random triads into some logical connection

SA

It's easy to analyze and musically rationalize something that's already been done. But it's hard to generalize about what can or can't or should or shouldn't be done because in art you can do anything you want. But one man's close harmony is another man's dissonance so it's a case by case scenario for me. It's all about HOW and WHY you do it. Same with complex rhythmic components.

The kind of music I like to play, hear and compose follows western harmonic, rhythmic and song form norms found in BeBop, classical, R&B, Celtic, Latin and black gospel music no matter how obscure and most importantly - does not come across as contrived or contrarian.

There's ways to get into a lot of chromatic things, dense chords, odd time signatures and lottsa key modulations and be deeply musical because it serves the music (See Ted Green's "Solo Guitar" CD, Dave Brubeck, Sergei Prokofiev or Frank Zappa) and there's also ways to do all that and sound like you're bullshitting. I used to say "good taste is universal" but it's really not - now I say taste is in the ear of the be-hearer.

https://drive.google.com/open?id=1a376xiSs4NS-DMUkculokTnQ6t_ewTkT

The changes are not really my taste but I made a quick exercise of it this morning for a warmup. lol You get all "one-take" clips with no refinement! hahaha
So in my opinion, It all starts with getting familiar with the progression. So what I did, sorry about the roughness - I slammed this together pretty quick this morning... So here is AN approach, not THE approach, and not necessarily MY approach, it's just what I did at the moment to take a closer look/listen to your progression. hearing it/singing it always makes all the difference I find - especially if one is trying to make decisions as to whether or not one actually wishes to pursue it further. So - what I did here...

1) Created a backing track from scratch to support some exploration.

2) Wrote a quick melody that outlines the changes (I interpreted it as Dmaj7 AbMaj7 BbMaj7 C7) And as such, I decided to play "changes" for each chord - D Lydian (A Major) Ab Lydian (Eb Major) and Bb Lydian (F Major) and C Mixolydian (Also F Major). I could have approached it as every chord being Dom7 also, which would have really opened up a lot of other things tonally (Dom7 chord can take any tension...) But I didn't feel like doing that... Also a "one scale fits all" approach didn't seem suitable here. I suppose an F "mixed minor" kind of thing may have worked out okay, but I didn't try it out yet specifically (Although like Steve says, you can skew the definitions somewhat depending on the context to justify your explanation, I mean it's all about the "pool of notes" being used. Fminor uses 7 of 'em, so only 5 left - that means that whichever way you chose to explain it there is going to be an overlap in the notes being played...) So yeah is it the most beautiful melody ever written? Well not to everyone that's for sure but I'll give it a chance and listen to what I did and decide what I liked or disliked about it and refine and modify it further later on if I feel like it... The melody is just an idea, a quick sketch...

3) I then copied and pasted my melody every second 8 measures and left an open 8 measures to solo over... Not in the spirit of creating a face melter, but rather to get familiar with the progression and work some things out. And no, it's not beautiful music - it's just a starting point.

4) One approach is using my ears and reacting to the changes - getting as close as I can to getting interesting things happening while trying to utilize and leverage what I am already familiar with. It's tight, as the changes happen pretty quick (1 bar and it's on to the next one!) And of course, gotta listen back and reflect on the decisions that you made...

5) Another approach is to be cerebral about it and actually REALLY try to nail the notes that fit with the chord while leveraging your existing vocabulary . It requires a bit of understanding of how music works, and ultimately the end result would be something that is both interesting to listen to for your audience as well as being fun to play. Once again, take a listen after you do it and be critical...

So while you are developing a chord progression, it is probably worth noting that it might sound like an exercise for a while as you flesh things out.

Is what it is, hope it helps. Next time I'll use a Stick...

See, this is why I ask you guys. You all bring different thoughts into the mix.

The good Captain most directly answered what I asked. His approach follows set styles although he recognizes the difference in taste of others.

Steve of course cleverly recognized a scale that incorporates root notes. The fact that I used 10 or 11 of the 12 notes available kind of negates that.
As he said, chord qualities and poetic license. Notating what I did, I found most easy to do with a neutral key signature (no sharps or flats; Cmaj, Amin au natural), and applying sharps and flats as needed.

And then there is J. Scott. What an excellent take on these chords. I really didn't imagine this in a jazz funk style, but there it is. I also recognize he has a multitude of approaches and this was just one.

I love it. Keep it coming.

Honestly, I found your post confusing. You want structure, but you want no key center or rhythmic center. You want to use most of the chromatic scale but want your music to be accessible (even though you may not have explicitly said so).

Listen to some Ornette Coleman.

Yeah, I noticed the post was a bit confusing based on the responses, for multiple reasons. Some of this Ornette Coleman stuff sounds fun and some of it just sounds bizarre to me. Thanks for the tip.

Part one: Describing what I did in one song ~ 30 years ago. This was just an example, and although it does shift keys a lot, the scales used are normal scales albeit with shifting tempos and dynamics. I think it doesn't sound too out there until you take it apart. Talking about music without hearing it is kind of like coloring about ballet. It just doesn't add up to much sense.

The purpose of part one was only to describe something I found out about myself that connects what I like to hear with what I like to write.

Part two: What I was asking for. I was hoping to find out what other people know that is a signature of their writing styles. Do people strongly adhere to set styles? Do they have certain recurrent harmonies? If we listen to their music, are there any clues that let us know it is theirs?

Still, I am enjoying every response as they keep adding valuable experience to the story. There is analysis of my chords, discussion about approach, a song example with description and suggestions on music. This is great!

Well, I thought that it would be cool to maybe take a swing at this with the Stick, y'know just sort of make something up and see if I liked any of it. This time, I superimposed a "one scale fits all" thing over it, F Major - I know, weird right? But think of it this way, since I played all major triads (no 7th) they can imply being a dominant7th chord, OR a Maj7th of some sort - since the bass side is not supplying the 7th, the pool of notes I am playing over it "fills" that in, leaving the listener's ears to hear if it's any good... And obviously you might not rip every note of the scale over each chord either, so it is what it is... Here is a brief intervallic breakdown of what I did...

So Fmajor = FGABbCDE

Over D Major (DF#A) FGABbCDE equals #9-11-5-b13-b7-R-9 intervallic-ly speaking it's a cool pool of altered notes... Altered Dominant 7 here...

Over Ab Major (AbCEb) FGABbCDE equals 13-maj7-b9-9-maj3-#11-#5 Lots of sonic "flavour" so to speak... A heavily altered maj7 or again, altered Dom7

Over Bb Major (BbDF) FGABbCDE equals 5-13-maj7-R-9-maj3-#11- Major 7th, as F Lydian as it gets...

Over C Major (AbCEb) FGABbCDE equals 11-5-13-b7-R-9-maj3 - Dominant 7th, definitely C Mixolydian for this chord...

Anyways thanks for the cool discussion - Just another of many different approaches available...

"Play Whatever you want, just make sure they're the pretty notes..." - Unknown music genius

And hey Daniel, it would be cool to hear your original riff perhaps?

Daniel, I love that people come from different places, and are often going to different places, and we all somehow meet up in the middle of it all, while still going off in our own directions.

I was heavily anti-influenced by my music school composition and studio professor, a Mr. Jackson that I talk about from time to time here in Stickland. He was a 12-tone serialist, and never saw chromaticism that he didn't like. But what he did not like was tonality, and also the sound of a guitar with overdrive or distortion. Which is odd, because some of the rockers can be the most atonal and experimental with rhythms and tonalities.

But I came up from gospel roots, and then church music classical music, and then went to rock and prog rock. I am not a jazz fan, usually because of the lack of simple melodies and riffs, and I am not a huge fan of tunes without a tonal center, even if it modulates from time to time and place to place.

I love songs with a tonal center of, say, A, but that shifts from major to minor, and plays heavily with chromatic basslines moving in counterpart with thick chordal melodies on top. I dig the occasional Mothers of Invention and Zappa, but I do not enjoy, say, Schoenberg and the like.

"Hey, Professor Jackson, 12-tone serialism and atonality is soooo 1920s! Hit that overdrive pedal and rock it out with a electric drill or something!"

But I love that we all love different things. And where jazz can intersect with some metal, tinged with classical and fueled by the blues, that's where I like to rock it out.