Of course, the main requirement with all this type of low light, long exposure photography, is that your camera is able to be set manually in both shutter speed and aperture setting and have the "B" (bulb) setting facility. You may also find the need to operate your camera's focus control manually due to these light conditions. A remote shutter release is fairly essential too.
Have a low ISO rating of 100 - 200 but for creativeness, you may want to set it higher.
Firstly, we'll take a look at fireworks.
You will need, with your manually adjustable camera, a wide angle lens, or zoom anywhere in the range of 18mm - 200mm, extra fully charged batteries and a torch, just in case, tripod, remote shutter release, if possible and a piece of black velvet material. I will explain later.
Arrive on the scene early, preferably in daylight, so that you can ascertain where the fireworks and rockets will be launched from. Check out the breeze, so that you can set yourself up downwind of the smoke.
You may find it easier if they are to be launched from just the one site, but if there are multiple sites, you may have to check which site will be best to work from, then determine your best vantage point.
If you can talk to the organizers and explain that you are on a special assignment, I am sure they will only be too happy to advise you of the best viewing area, and so that you can see, even in the dark, where they will be launched from. It may seem to you that it is a lot of messing around, but it's best to be prepared on all fronts.
Once you have yourself all set up and fully established in the right position, it may be a bit of a wait till it all starts to happen. Go through everything with your camera, even take notes if necessary. These events don't happen every day, so you want to be sure all is in order.
When the event is about to get underway, go through everything again in your mind to be sure you are ready.
The camera's on the tripod, the remote shutter release is fitted and the torch is handy. Make sure camera's on "B" setting, the aperture about f/11 lens is at its widest angle, the piece of black material at the ready, stay calm.
As the first rockets are launched, treat them as test cases. Look through the viewfinder or at the viewing screen as the firey streak shoots skyward, with your hand on the lens, ready to adjust the composition when the rocket bursts. If you are using a zoom lens, adjust it quickly for the best results. Depress the shutter halfway to ensure the autofocus kicks in, and if so, take the shot. If not, you'll probably have to wait for the next burst using manual focus.
Instead of just doing a lot of single exposures, you can if you want, do 3 or 4 exposures on the one frame. This is where that bit of black material comes in.
Once you've had a couple of practice shots and you're happy you've got your composition and focus in order, place the black cloth over the lens and open the shutter with the remote shutter release and lock it open. Then, at the moment you see the fiery streak of the next rocket being launched, uncover the lens, but as soon as the sky goes black after the burst, re-cover the lens again.
Do this for the next couple of bursts and then close the shutter again, by unlocking the remote shutter release. So now you will have 3 or 4 bursts in the one frame and hopefully all different colours. This tends to look better than just the one burst per frame. But that's up to you and I'd encourage you to experiment taking shots in other ways to come up with different results. By all means, use your own imagination.
Before we go any further, I might just mention, that if you intend taking photos in public places, and especially places where children are prevalent, and they are quite prevalent at fairgrounds, you just might get questioned by security, in reference to your activities. So I'd advise you to take a couple of friends along, then you won't look so conspicuous and they may not bother you.
Fairgrounds can provide a veritable smorgasbord of colour, bright lights and facial expressions, both during the day and especially at night.
Your gear should include, again, a camera that is suitable for being set manually, a zoom lens anywhere in the range of 18 - 200mm, remote shutter release and tripod. Also a torch and extra batteries, just in case.
During the day, you can get a bit of practice in with all manner of exposures. Playing with aperture priority. Blurring the background or having it clear and sharp. Using shutter priority, 1/125 - 1/250 second to keep images sharp or getting down to 1/30 - 1/15 for some induced blur on spinning rides (using a tripod of course), or get in some 'panning' practice at the dodge'm track. But when the lights come on that's when the fairground really starts a-jumping'.
You are now in the twilight zone and for the next twenty minutes or so, you can take shots of the lights in that half-light, but now you will need to start using that tripod. I think the best time is at night. You can then get those spinning rides at really slow speeds that become just coloured blurs. Use the "B" setting here with exposures of around 5 - 10 seconds, aperture about f11, but try all sorts of things. Forget the rules and just have fun that's the main thing, after all, your there to enjoy yourself too.