Okay!
So, one of the main similarities between these two cultures is they were both polytheistic (believing in more than 1 god). They believed in gods of certain elements, such as water, sky, etc. They also had passions for arts, astronomy, and other areas.
A difference between these cultures, however, is that Mesopotamia had kings, while Egypt had Pharaohs, seen as literal gods. Another difference was their view of the afterlife, that being Egypt viewed it as a blissful place, while Mesopotamia viewed it as a true hell.
We won't supply a thesis statement for you, since that's something for you to do on your own! =)