Compare inner and outer planets=Differences: Outer are larger, mostly made of gases, have many moons, farther from the Sun than the inner planets. Inner planets are smaller in size, few or no moons, closer to the Sun, mostly rocky. Similarities: orbit the Sun, part of our Milky Way galaxy, they all appear as stars in the sky from Earth--can't think of anything else.
Compare types of vehicles, cats to dogs, types of food, different holidays, etc.
Hope this helps you out a bit more.
