Here's a short but quite tricky picking lick in D-dorian/blues. The first part is pretty straight forward but it's the last 7 notes that might be a problem.
The reason for this is that it shifts from being 3-notes-per-string to 2-notes-per-string in the middle of a pretty fast run. Very useful to get down though since it'll open up your possibilities a lot when improvising.
Once you've understood the idea try expanding it to the other strings as well, this way it'll be much easier to use it spontaneously while improvising.
One of the best habits you can develop is to always expand and make variations on the things you learn from your favorite players. That way you'll actually learn from them instead of simply copying.