A headlamp is recommended. This has the advantage that it is in a defined place (head) and quickly to hand without occupying a hand.
A very stable tripod is recommended here! If possible, even with four legs instead of the usual three. It can happen at night that you accidentally run into the tripod in dark surroundings, and if it then falls over and the camera is damaged, the cheap tripod has become a very expensive tripod in one fell swoop.
Dark clothing and shoes are essential. Why is that? During the long exposure, we move through the photo and paint the desired figures with our light. If we are dressed in dark clothing, we will not appear in the finished photo unless we stand in one place for too long! If we wear light-colored clothing, the time we can stand in one place is dramatically reduced! And we may end up with our light-colored sneakers in the photo a few times, which ruins the overall impression!
If we work outdoors, our clothing should also be suitably warm because it often gets “fresh” at night.
To avoid having to walk to the camera every time, a radio remote release is a great invention. In some cases, various cameras can be controlled via a suitable app on a cell phone. This gives us the added advantage of being able to check the photo straight away.
We can easily control the camera in bulb mode using the lock button. As long as the lock button is engaged, the exposure takes place. Once we have completed our light painting, we can release the lock button and have completed our photo.
We can also use flashes in light painting, for example to bring people into focus in the picture. The trick is to flash the person from the side with a suitable flash output. The flash is also controlled manually!
It is important to know the location. Otherwise there could be nasty surprises and a high risk of injury, which is easy to assess during the day when it's light (nobody likes to fall). If the location is not around the corner, you should at least carry out a virtual location check using Google Maps (or similar)!