So I have read again and I saw a few more misunderstandings.
"L'echec" is "the failure" if you mean the chess game then it's "Les echecs".
"Les" is a "the" but as a plural.
Exemple: Les chat"s" (the cat"s")
Next : “Thank you,” I answered sadly, “but I know I’m not even half as beautiful as Elise.” “Eh, pas!” Caroline cried
Instead of "Eh, pas! " you could say "Je ne suis pas d'accord!" (I disagree!) because "Eh, pas!" doesn't mean anything or it's sound like an incomplete phrase.
Next: "Ferme la bouche" She’d just told me to shut my mouth, albeit in a kind way.
You said my mouth but you wrote "ferme LA bouche" (shut THE mouth), if you meant shut your mouth then it's "Ferme TA bouche" but then again it wouldn't be correct to say that.
It's better to say "Tais Toi." if it's familiar and if it's formal it's "Taisez vous."
I don't see anything else for now. Either way it mean there isn't anything more to say or I need new glasses.
The more the difficulty, the more the glory.