I could just make out that she had a little smile at the corner of her lips.

She watched him for a second, a smile playing at the corner of her lips, then turned away.

There was a tiny smile about the corner of her lips.

A smile was playing at the corners of his lips.

The corners of her lips turned up as she watched them.

The corners of her lips turned up in a small smile.

The corners of her lips were turned up at the ends.

He bit down softly on the corner of his lip.

Then the corner of his lip curled just a bit.

A faint smile played around the corner of his lips.