Pay attention to your body. You will dehydrate faster. Shop, take pics, enjoy the little things. I love just looking through the stores. I enjoy the shows. And visit the Animation building. My kids will go to do the drawings, and I enjoy just hanging in there watching the clips.
I don't ride most of the coasters, and many doctors will advise no coaster, so my kids head for a ride, and I will people watch, shop (rarely buy, save it for the last day) and enjoy shows. While kids are doing Star Tours and Space, I watch the Jedi Academy and check out the Little Green Men store. While they do BTMRR, I hit the petting zoo. They do Indy, I check out the pin store in Frontierland and NOS... Lots to see and do!!
Oh, be prepared for daytime sickness. A good friend had just discovered she was pregnant last year before Christmas, and we were all at
Disneyland. She was 7 weeks along and so happy she hadn't had Morning sickness. She and I were sitting off while her hubby and my kids rode Maters and Racers (that's how she told us, her doctor said no coasters...), when suddenly she started feeling ill, and spent the rest of the day trying to stay out of the bathroom. I think it was simply her body deciding too much activity.