Decided to post my riff after the encouragement I got from many of you. As I said, it's not much, but I am proud of it.
I returned to the CAGED System and based my Riff around Syn's Tip in Lesson 29, where he encourages us to stay in one position when playing and making the most of it. To demonstrate why that is benefitial I played my chords in different positions first and the main riff all in one position.
Here's the theory behind it: My Riff is based around Dm, the Chord Progression is Dm-F-G (Dm-A-Dm-A-F-A-Dm-A-G-A-G-A to be exact). The main riff is sweeping the arpeggios (I think) all based around the fifth fret, using Dm in the Am shape, A in the E shape, the C shape for F and the D shape for G. I always play D, F or G arpeggio on the up sweep and the A on the down sweep.
I am doing this in so much detail to get some extra practice with the CAGED system. Also I am aware there is no F# in my key, which I play when sweeping the G arpeggio but I thought it adds a nice touch.