But when it comes to dolls, it is much better to find fun angles, props, good light, and almost like a painting, you have to find the right position in "thirds", meaning, divide in thirds with imaginary horizontal and vertical lines:

...And place your doll (or main object in the photo!) on the two thirds to left or right. For a composition, it is more pleasing to the eye and gives you more space to play with if you .
Just practice a lot, if you are like me that wants everything pictured right in the center :oD

And a different photo with props, and placing the doll on the third side, but I think there's too many things to distract the eye:

Cropping the image a little, makes the eye go to the doll easier:

Have fun practicing!