Taylor Swift - I'd Lie Lyrics Meaning

I don't think that passenger seat
Has ever looked this good to me
He tells me about his night
I count the colors in his eyes

Taylor says that she and the guy she likes are pretty vocal and open to each other. The guy tells her about his night, and as she is there for him.

He'll never fall in love he swears
As he runs his fingers through his hair
I'm laughing 'cause I hope he's wrong
And I don't think it ever crossed his mind
He tells a joke, I fake a smile
Cause I know all his favorite songs

I don't know if she means he jokingly says he'll never fall in love with her, or simply he is saying he won't fall in love with anyone. Of course, she secretly wishes that he's wrong. She loves him alright, but he doesn't know. It might never have crossed his mind that she may actually love him more than a friend.

And I could tell you
His favorite color's green
He loves to argue
Born on the seventeenth
His sister's beautiful
He has his father's eyes
And if you asked me if I love him
I'd lie

She just states here the facts about the guy she likes and how she almost knows everything about him. But if anyone asks her if she is in love with him, she would lie and just deny the whole thing.

He looks around the room.
Innocently overlooks the truth.
Shouldn't a light go on?
Doesn't he know that I've had him memorized for so long?

This certain guy might be a classmate or officemate... or simply some other guy she's in a room with together that doesn't know that she likes him. She knows exactly what that guy will do, or what that guy wants since she says that he could say "Shouldn't a light go on?" once he enters the room.

He sees everything black and white.
Never let nobody see him cry.
And I don't let nobody see me wishing he was mine.

"black and white" means the guy she likes is someone who takes things seriously. He knows what is right and wrong. Therefore, he doesn't want to let his ego down, instead he hides his problems. In turn, Taylor hides any sort of her feelings towards him from other people.

He stands there, then walks away
My God, if I could only say
I'm holding every breath for you

She looks at him from afar, or he approaches her then walks away... if he only knew how much she is in love with him.

He'd never tell you
But he can play guitar
I think he can see through
Everything but my heart
First thought when I wake up is
My God, he's beautiful
So I put on my makeup
And pray for a miracle

She says that the guy she likes has a hidden talent in playing the guitar, and she is aware of that. He is not ignorant towards other matters, except regarding her feelings for him. Of course when we are in love with someone, they will be our first thought when we wake up. We get fascinated with him, and how unattainable he is. We end up fixing and making ourselves look good just for him. That's how Taylor feels as well.