what i like doing is looking at paul gilbert for ways to scramble your mind into very creative ways to play the notes of a modal run.
he is very good at visually showing you this in his instructional videos all over youtube and on DVD.
if you need help starting off in the right direction, i highly recommend him. but first you need to know where to play for the key you are in, and the phrasing you want to say. guitar playing is just like language speaking. say it too fast without knowing what you want to say and nothing will come across.
say it in a way people will remember it, and say it with meaning and purpose, and it will always be clear to understand and have a connection to the listener.
i have a habbit of choosing minor notality - i just phrase in this naturally and only mix a major in once and a while...and usually by accident.
IMHO the day anyone says they know anything is the day they limit themselves. no matter what anyone says they are always learning and as long as you are constantly searching for improvement to get somewhere
FWIW i have tried to follow paul gilberts "player's rule"
which he stated off of one of his videos that when you sit down to play, sit down to learn something new, no matter how small or large it is. do this once a day - or once each time you sit down to play.
after a few months you will be surprised, and with practice, you can retain the knowledge you have gained