Watch the Blazing Iommi online guitar lesson by Angus Clark from Hard Rock Survival Guide: Lead
There are a few shortcuts to getting the Iommi style. One is his use of trills. Another is his use of finger slides. He is a primary influence on me and how I approach pentatonic fingerings, using finger slides and position shifts as opposed to just box shapes. Early in the solo there are a few phrases that move from the tonic to the 2nd scale degree, which is also hallmark of Iommi's style. This is like baby steps to introducing diatonic material into a pentatonic solo.
When the rhythm track opens up I do two things to kick up the dynamic of the solo: I hit the wah-wah and I play a bunch of unison bends. Unison bends get you more sound because you have two strings ringing instead of just one. In this case I am using the Wah in the basic toe-down on the beat style. Additionally, the unison bends are "loose", meaning the bent note is relaxed against the pitch in order to be intentionally out of tune with the fretted note so that a bunch of overtones are created. This is where we are using the sonics of distortion to create more sound that you could with just a JC-120. And why would you ever use a JC-120? It says "Jazz" right on it.