General:
* Grinning: Implies a wide, open smile, often with teeth showing.
* Beaming: Suggests a bright, radiant smile, often associated with happiness.
* Laughing: When the smile is accompanied by audible laughter.
* Smiling widely: A more literal description, emphasizing the breadth of the smile.
More descriptive:
* Gap-toothed grin: Emphasizes the size of the smile and the display of teeth.
* Ear-to-ear grin: Describes a smile that stretches all the way to the ears.
* Cheeky grin: Suggests a playful or mischievous smile.
* Radiant smile: A beautiful and glowing smile, often associated with joy.
Figurative:
* A smile as wide as the ocean: Hyperbolic, emphasizing the vastness of the smile.
* Smiling from ear to ear: A common expression, implying a very wide smile.
The best word will depend on the specific context and the desired effect.