I have a great lick that i show my intermediate/advanced students....lets see if i can tab it out on here...
----------5678---
---------6----7--
--------7------6-
---5678----------
play as 4 groups of 3, triplets will work as well
i also get them to reverse it..
----------8765---
---------7----6--
--------6------7-
---8765----------
then i make them count with accents to re-phrase it
1.2.3., 1.2.3., 1.2.3., 1.2.3.
1.2.3.4., 1.2., 1.2.3.4., 1.2.
1.2.3.4.5., 1.2., 1.2.3.4.5.
making string accents on the 1 of each group, it's a hell of a way to learn control over your hand.
I agree with HaVIC5, speed will come with time and it will happen faster with the more control one has over their hands.
I also use odd meters to teach with and of course using accents too.
x=1/16 note rest
------7-x-----5-4-----------
----------5-x-----7-5-0-5-7-
--5-x------------------------
-----------------------------
This lick is in 13/16
accents are like this:
1.2., 1.2., 1.2., 1.2.3.4., 1.2.3.
as before accents on the 1 of each group
(for fun replace x with the note before it, turns into a very bouncy, carnival type riff.) ENJOY!

JON