The leaves looked as though they were on fire—gold, orange, red—blending together into flames that licked the sky.
Leaves don't blend together. Get rid of "blending together into" and change it to "forming". Then the leaves will still be... leaves.
Liar had never come to mind and yet, there it was, glaring red in front of his eyes, as if written across his line of vision with a Sharpie.
Trim the fat. Get rid of "with a Sharpie". You don't have to specify what it was written with.
“Tony!” she had exclaimed, face immediately rising in color with embarrassment.
You need to say "her face" and you don't need to say it was rising in colour "with embarrassment". It's unnecessary and excessive.
He had come to the conclusion shortly after finding her with Gary that Darci could no longer be apart of his life.
"Apart" means "away" and should have from after it. You need a space between "a" and "part".
Images flashed through her mind—Tony, crashing into her plate of food smearing a combination of ketchup, potato salad, and ranch dressing onto his new, dress shirt, and then onto her white skirt.
"New, dress shirt, and..." doesn't make sense. Is it a new dress shirt or new dress? There's a punctuation confusion here.
He stilled cared for Darci, more than he would have liked at the moment.
"Still" not "stilled" and there should be a "to" after "liked".
They both lost themselves in the memory of such an innocent get-together turning into their on little party in her friend’s closet.
"Own" not "on".
Either will I.” Their eyes connected and the world around them melted.
"Neither" not "either". Eyes do not connect, they meet.
Tony sighed, trying to fight the internal instinct to comfort her as he watched the rivets of tears stream down her face.
Rivets are bolts. I think you mean "rivers".
Had she been unhappy with Tony?
This sounds like more of a thought-based question, so you should end it with "him", not "Tony". Another reason is that you used his name in the previous sentence and you need to rotate pronouns.
“You saw things distancing between us. Even I can’t deny it, though I want so much for things to go back they were. You know they can’t, Darci. You know that. The damage is done and I don’t think this accident is fixable.”
This is said by the same person who spoke in the last paragraph, so there should be no paragraph break.
She let them run, let them be free, because she knew this wouldn’t be the last tears she shed over Tony Denaro.
"These" not "this". You're referring to more than one tear.
Aaw, I haven't read a good mushy romance story in a long time. It's really cute, but I think that the ending is very slow and lingering and it could easily get boring. Be careful and good luck with this piece!
