Wooohooo, today I realised something terrifyingly evident.:D

I practiced walking lines over some standards and blues cycles, because my teachers wanted me to create lines that are leading better. I spent some sweaty hours doing that, then I started soloing for fun...and realised that these to things (walking and soloing) are the just same...I mean there are more notes in your solos and they are more elaborate, but their logic are very alike.
Firstly there are your scales going upon your chords and of course there are the chordal notes. That's what you have to connect with the invisible chain of passing notes and linear approach. You only have to find which are the notes who tend to lead somewhere...the seventh notes, your alterated notes, passing notes between two chordal notes...etc. Then you go where these notes want to go.
When you make a walking line you must use them as simply and logically as you can. But if you do so you don't have to use your boring patterns all the time and can leave the first-beat basic tones alone for a while.
When you solo you do the same, but you can feel free using more chromatic approaches, semitones on beats, chordal subsitutions and you can circulate around the chordal tones before jumping on them. You can also jump as big as you want to create nice melodies.
If you have your leading tones in mind you can forget about difficult calculations with scales...you only have to think about which are your chordal notes, and which are the leading ones. And these ones bring the colour in your music.

...well, this is theory...now I only have to practice how to do that.:P :DDD