I practiced for a long time, this "mixing modes" thing, and I could never get the hang of it. After a while, though, in jam sessions, we'd play something in B Minor (Aeolian), and I'd unconsciously throw in the b9, which isn't exactly mixing modes, but it does imply a Phyrgian sound over an Aeolian chord progression. Then, two seconds later, I'd go back to using the normal 9. I'd run through B Minor Pent. and then do a little legato triplet thing (I'll tab it out... something I accidentally did one day, but it sounds cool) using the natural 6 of Dorian. I realized I was finally mixing modes, as I had wanted to do. I find it a lot harder to mix major modes, because most of the things we jam on are in a Minor key. Putting forth conscious effort to mix modes, I have found, doesn't work. It has to just flow... How can you get the flow? Not constant practice, but rather constant jamming. I've learned more in 10 minutes of loose jamming than in an hour of structured practice.

Key: B Minor, Implied Mode: B Dorian
(only pick first note. All the rest are hammer-ons and pull-offs)
e|----------------------------|
B|10-9-7-10-9-7-10-9-7-10-9-7-|
G|----------------------------|

I commonly pull off (no pun intended) this lick on the high e string, hitting the 1, 2, and b3 of a minor key, but I accidentally missed and did the lick on the B string at a jam, and it sounded cool. I later dissected the notes and found I was hitting the 5, natural 6, and b7, implying the Dorian mode.