Hey,
I've been following along the cartoon dog tutorial and everything is going fine until I take a look at my perspective view and see that the other side of my model does not look like the other side. Whereas the the guy doing the tutorial, his model is perfectly symmetrical. Is there something I missed? Is there something I should have turned on so that all changes I make on one side are reflected on the other side?

This is the only thing preventing me from finishing up the tutorial. Any help is greatly appreciated!