I used to hate them but have had quite a few over the last few years. My number one tip would be to go onto YouTube and type in mri scan sounds. There is a really good video on there and it goes through all the different noises, knowing them before hand really helped. Some sound like workmen digging the road up, others are like buzzing sounds but it did really help.
I kept my eyes closed and was terrified of opening them on a few of the first, I agree with pp that it would be best to see where you are going and its just like a smooth surface above you.
Tell them you are nervous, they know how to calm people down, loads of people are nervousl.
I had one in a hospital in the North West, it was a new scan department and they had mood lighting and on the 'cage' over your head was a little mirror, there was soothing scenes playing on a TV you could watch through it. There was like a bar across the bottom and it moved like a timer for each of the sounds. It was actually the best mri I've had, maybe if you tell them beforehand they can get you In one like this if they have access. (the radiologist told me for my next appointment, when I got the letter, to ring and say I was terrified and ask if they could book me in at that department)
I have been in the scan room with my son when he had one, I sat at the back of the scanner and he could see and talk to me the whole time, well between the noise!
if you are really nervous perhaps they would allow someone in with you? I don't know of they allow for adults but worth an ask.
Anyway, sorry so long but I feel your fear, they are worse In your imagination and it will be over before you know. Another thing I do is count backwards from 1000 in my head to take my mind off it.
Good luck, you have got this x