I'm not really into steel wool these day, but as far as advice, I'd say try and keep your spinning hand in the exact same spot and spin as fast as you can. This will give you a nice tight circle and spinning it fast will give you cool bounce effects when the sparks hit a nearby wall.
here's one I did a couple years back that might describe what I'm trying to explain:
I would also suggest lighting up the rest of the scene a bit more especially on  and . Of course this is just my own opinion.