Here is my problem. I take a major scale in any Key. Lets use C. I pick any diatonic chord. Lets say Bm7b5. I'll play in this order: B,D,F,A,E. My ear notices that if I start on B and end on E, that sounds like a good note to resolve on. Nice and dark. C works well too. Then I'll take other diatonic chords and play the chord tones in different combinations and inversions and see what kinds of phrases/tonalties I get. I'll try to listen which notes sound conosant and which are dissonant. I try to come up with simple grooves and melodies but they all sound elementary and still kind of sound like Im just playing a C major scale. Its basically just playing the C major notes and chords in random order and seeing what works and what doesnt. I listen to someone like Jaco and there is all this movement and color and wonder exactly how do I come up with interesting melodies and grooves besides just playing Dm7 G7 Cmaj7 in linear fashion up and down.
I just don't know what do with all this knowledge and how to progress. I guess the only thing left is to transcribe music.
I'll try to address this.
You said:
"I take a major scale in any Key. Lets use C. I pick any diatonic chord. Lets say Bm7b5. I'll play in this order: B,D,F,A,E. My ear notices that if I start on B and end on E, that sounds like a good note to resolve on. Nice and dark. C works well too."
The problem is that you are
still in the key of C Major. You can't just pick a chord, such as Bm7b5 and expect to instantly be in B Locrian. You must construct a melody that resolves to the Final of Bº. This Bº HAS to be the home chord. How to do this in a Locrian Mode, not sure. This is probably the most difficult mode to work with. I can't even find any reliable examples.
The Modes can be grouped into three subclasses. Major, Minor, and Diminished. The three Major Modes are Ionian, Lydian, and Mixolydian. The three Minor Modes are Dorian, Phrygian, and Aeolian. The Diminished Mode is Locrian.
The easier Modes to work with are
probably Dorian, Mixolydian, and Aeolian. But I am only guessing. There does seem to be more examples around.
You said:
"I try to come up with simple grooves and melodies but they all sound elementary and still kind of sound like Im just playing a C major scale. Its basically just playing the C major notes and chords in random order and seeing what works and what doesnt."
I'd start with the progressions from the examples I posted and see if you can create new melodies or try to improvise over them. Keeping in mind to end the melody on the Final and even starting on the Final. Don't bother with inversions. Avoid 'random'. Compose something. It's not easy, by the way. Start with something you are familiar with and vary it. Stick to triads, forget seventh (or higher) chords for a long while.
And, starting with a C Major chord - in an Ionian or Major Key - and a melody note of E does not make the melody in Phrygian.
You said:
"... how do I come up with interesting melodies and grooves besides just playing Dm7 G7 Cmaj7 in linear fashion up and down."
This is the result of attempting to play different so-called Modes over each corresponding chord. Using your example, Dm7 G7 Cmaj7, and playing D Dorian, then G Mixolydian, then C Ionian will give you what you experiencing.
Doing that over a bunch of ii-Vs, or Dominants would give me a headache.
To improvise well, start by singing over the changes - and KNOW the melody (yours or someone else's) - then try to play along with what you singing. If just flail or run scales (or so-called modes), that's what you will sound like.