To set up the long exposures, I always shoot on a tripod. Sometimes, the shots are up to 30 seconds long and without a tripod these would be impossible. Since I am shooting longer exposure times, I also try to keep my ISO at 100 to minimize any noise in the image. Even shooting at ISO 100, because you're shooting a long exposure, there will be some noise in the image. Most of the time, this can be removed in Lightroom, Adobe Camera Raw or whatever image processing software you prefer to use. For most of my night photography, I shoot aperture priority. However, this is if there is not a lot of change in light (i.e. shooting a cityscape). This allows me to control for my ISO and I can get the shutter speed I want by adjusting my aperture that I am shooting at. Because I was setting up for the shot before the ride started, the light that my camera metered for was much different than what I would be shooting at while the ride was going. I used aperture priority as a general starting point and then switched over to manual to lock in my exposure.
The key to shooting the moving lights was experimentation. Some shots that I got weren't that cool at all... But this allowed me to change my settings. For this, I knew that I wanted a gap in ferris wheel, so I played around with my shutter speed to get the right time interval to accomplish this. The light pattern when I shot this was coming from the center to the edge of the ferris wheel. I liked the spiral pattern this gave and was much more interesting than just a solid wheel of light. This is another thing about long exposures: learn to see beyond what your human eye can see. Playing around with your settings will give you different effects and it's up to you to visualize that.
When doing night photography, you have to be patient. For these shots, they probably took 10 minutes each to set up and timing it so that my composition was correct. I knew that I wanted a unique pattern in each, but had to make sure that I had all my settings correct and had an idea where the ride would start and stop during my exposure to get the effect I wanted.
Sometimes, the normal shot looks best. I thought this would be a cool ride to photograph with a long exposure when I was first walking around the fair. I thought I would like how the streaks looked. Turns out that there wasn't as much excitement to the image and didn't feel like there was much going on. Looking back, a cool way to do this would have been to take an even longer exposure and have the ride stopped at the bottom. Perhaps that would have added to the image and portrayed the ride dropping.
The above shots I liked the best out of the whole night. I think that this told the story of the speed and excitement behind some of the fair rides. Unfortunately the sun set quicker than I thought it would, so I didn't get the blue skies that I typically like to have in my photos. I recommend shooting at blue hour because it gives the image a little more pop. Going back, I probably would have shot this at blue hour to see how it would look without the dark blue being added in during post-processing. However, even without the blue in the sky, I still like the story that the light streaks tell and how it goes to show the lights and fun of the fair rides.