Blues Scale in Jazz

I thought all you had to do to play Jazz was just hit a bunch of unrelated notes and, if a note sounds particularly bad, then make sure you hit it with emphasis a second time to show that you really did mean to play it the first time!

What I really need to get a handle on are those Maj/min chords and those weird travelling chord steps that land "in between" the 7 modal steps
 
Diminished 7th chords are the in between chords. You can put them in between any 2 chords 
 
Working on chord function and progressions (Changes) can help. Where the bass notes move and progress defines it. Too much time is given to the words or what is written down about this subject and not enough listening to the sound. It's the sound of it that's important. 
'Take the sound of the modes
 
Ex. A minor Dorian - if you pedal an A in the bass and play a C and D triad you get the sound.   Dorian
Any chord diatonic to G major will sound Dorian over a pedal  A or A in the bass note. It's where that bass note takes you next that guides a song. "Where is This going"? is the question and answer. IMHO it takes time to find the sound in writing music. Using preconceived chord progressions always leaves me with "this just ain't right" feeling 
 
Each mode has a sound and easy to find. Let's do the Ionian mode(Tonic)
 Pedal C  ex. (F to G over C bass or any chords diatonic to C major)
 
Phrygian with C in the bass makes it in the key of Ab. Pedal C over Db and Eb or any diatonic chord in Ab for Phrygian. Etc.
 
modal music doesn't move much and if you want something to play when you have a vamp one one chord knowing the above can help
 
 It helps me to simplify and break progressions and changes down to the following;
 
      Sub dominant sound ( minor sounding or major sounding chords that you can repeat and don't necessarily go any where but could) This includes unaltered dom 7 chords 
 
      Dominant sound( chord sounds that just has to move)
 
      Tonic sound( ahhh That's where I want to be for the moment  (( sub dominant))  )
 
 
 
 
 

3 note voicings on guitar are very useful, I think they came out of the Big Band era. I found it very useful to learn all fingerings of the standard chords (maj, min, 6th, maj7, min7, dom7) in each inversion on the low E, D and G strings. You can get so much mileage out of these and I find myself using them in all styles of playing. 

If there is anyone needing or using this Fred let me know and I will keep adding to the info. If not I hope what has been written above has helped someone. If you want to hear what 3 note chords sound like in a musical context click on SONGS link below and listen to Autumn Leaves. It's full of 3 note chords
 
P.S. I must mention I had to play Autumn Leaves in Am ...........   we all know why