Start by adding some blue notes (flat 5s) to it and then experiment by adding some chromatics.

Im posting a lesson addressing the blues notes and the blues scale later on today so don't forget to check my Instructors page !

There is also a tutorial there called "Play Lead Guitar" which may be useful.

Here is a link:
http://www.guitartricks.com/lesson.php?input=8157&s_id=73

If you have any questions, ask a way, don't be shy !