what’s a good way to start a comparative essay?

what’s a good way to start a comparative essay?
I have to compare the three contexts I’ve been studying (My Sister’s Keeper (NOVEL), Sive (PLAY) and The Constant Gardener (FILM)). They have to be compared on the theme of isolation!

Just looking for an example of how a comparative should be started.

If you’re comparing the theme of isolation in three contexts, you might want to approach the essay in a manner like: “no matter the context, there will always be key themes that are essential to a narrative. For instances the theme of isolation can be found in many contexts such as “My Sister’s Keeper,” “Sive” and “The Constant Gardener.” In this essay, I will demonstrate how the theme of isolation is comparable for these contexts.”

Something like what I typed above, but a little more in-depth and with better grammatical form.

Good luck.