Weeeelll... when I visualize MWI it's just the same as my visualizing the math of QM itself. I'm not sure how someone who doesn't know the math would visualize it. Presumably, using EY's configuration-space-blobs, like TheMajor used in his description.

Those aren't great for predicting the outcome of interference since you have to tack on the phase information, but they are very good for noticing when things aren't going to interfere at all.