Well, I thought you were going to be talking about a younger child, so what worked for us with our 6 and 3 year old might not work for you. We talked a lot about before we went about how nothing would touch or hurt them, and if they were scared they could just cover their ears and close their eyes until the scary part was over.
I did show the kids PHOTOGRAPHS of rides, but never videos, as I knew that would scare my kids more and they would build things up to be something they weren't. We went in September and most rides were walk ons, so I think that helped our situation, as we walked so quickly through queues, our kids didn't really have a lot of time to get scared! For example, dinosaur, the line was moving so quickly, we didn't have time to stop. My DD3 said, "mom this ride looks scary". But the people in front of us were moving so we just said, "Don't worry honey, oh look hurry up, we have to move quick, the line is moving". 99% of the rides we took the kids on, they loved. A few they said they didn't want to go on again, and that was ok.
I was more sympathetic about rides that had physical sensations that might be uncomfortable for them, such as TOT, and EE, I didn't force them on those rides. But HM, they had no idea what the ride was about, they were just scared cause the name sounded scary. Haunted mansion turned out to be their favorite ride!
For splash mountain, my DD was a bit scared, but we showed her all the people coming off the ride and how none were crying, all were smiling, etc. so she decided to try it. She didn't love it, but it didn't traumatize her or anything!
I find my kids need a bit of pushing, but 99% of the time they love it afterwards, you know your kids and what amount of pushing they can take! But I wouldn't spend all that money to have them only want to go on a merry go round and walk around all day. I could do that at home
