I usually get really motion sick on rides, even in the car if I'm riding in the back seat. I almost didn't go on GotG because going backwards on rides makes me super sick.
I had no issues on Guardians which I was surprised. The difference is that the ride is not free spinning. It is a controlled rotation that the ride uses to enhance the motion instead of "how many times can we spin you around" its, "how can we use the rotation of the vehicles to better serve the experience".
I sat in the front row. Instead of watching the screens, I watched the track in front of me and focused on moving with the rotations of the vehicle. The screens on the ride are meant to be environmental. They add to the ride but are not supposed to be watched.
I have now ridden twice without taking any medication/help at all and had no issues walking off the ride. I also ate a banana each time as we walked through the queue which helped my stomach feel less empty. My Spouse had to sit down afterwards because he was feeling sick and had been watching the screens.
Enjoy the ride! Be prepared and you'll be fine.