The light work is only half of the equation in a light painting. Making sure the location is visible is just as important, if not more so. Using bright lights or pyro make it tough to get a nice balanced exposure that really shows off your environment. This, in turn, can render your act of trespassing and wading through muddy snake ridden waters entirely pointless.
One solution is using a manual aperture lens. The f/stop on a manual aperture lens is set by the aperture ring on the lens, rather than electronically via the camera. This allows you to change your f/stop during the exposure. Jeremy Jackson, TackyShack, uses this feature of manual lenses in a ton of his work. I paid him a visit last summer in Virginia, and after using his Rokinon 14mm f/2.8 for the night I bought myself one the next week.
To create the image at the top of this post, I taped (duct tape, for the obsessively curious) a sparkler fountain to a stick and moved it around behind a friend. For the first 50 seconds of the exposure, the camera was set to f/8, ISO100. After I finished with the fireworks, I walked over to the camera, opened the aperture up all the way to f/2.8, and let the sky burn in for another three minutes while my friend stood perfectly still. The total exposure time of the photo was 212 seconds. Having your friend stand barefoot and motionless in a cold lake for nearly four minutes after raining hell fire down on him really brings out the sadist in you.
Below is the first attempt at the shot. The exposure was much shorter (43 seconds, f/8, ISO100), and the f/stop was also consistent at f/8 throughout the exposure. Staying at f/8 would have taken forever to expose properly and we would never have been able to capture so many of those glorious stars overhead.