Record a twelve-bar blues chord progression you can use to play a blues scale over. A simple twelve-bar major chord pattern in the key of C is: C-C-C-C-F-F-C-C-G-F-C-C. You can vary the pattern by making the first four C majors into C7 chords. Record this pattern several times to allow yourself room to improvise a blues scale over it.
Practice the C blues scale. A C blues will be a C major scale with the third, fifth and seventh notes of the scale lowered (played flat). The notes you'll use are C, D, E flat, F, G flat, A and B flat. The "blue notes" are the flatted notes of this scale and used to create a blues solo over a blues progression.
Play back your twelve-bar blues progression and try playing a few notes from your blues scale. Don't worry about playing complex musical licks. Play a note from the scale and hold it out. Slide away from the note, then play two notes from the scale. Make the first note fast and hold the second note out, but add vibrato to the note. Do this by keeping your finger on the note and rocking your finger slightly from side to side, causing the note to wobble.
Bend the strings of your guitar as you make up short musical phrases using the notes of the blues scale over your recorded blues progression. A musical phrase might consist of the three or four notes from the blues scale played ascending, with a string bend on the last note of the phrase. Try combining the bend with vibrato. String bending, vibrato, and sliding to and from notes is a key feature of blues guitar playing and will make simple guitar licks sound exciting.