Crescendo

A crescendo means get gradually louder. It is written as cresc. or as a hairpin that opens to the right.

The word means "growing", and the shape is a picture of it. What matters is that it is gradual: the whole point is the journey, so arriving at the loud end in the first bar wastes it.

How to spot it

A hairpin opening to the right under four quarter notes: get gradually louder.

A long angle below the staff, narrow end first, opening as it goes right.

Find it in thirty seconds

Find a crescendo and play it in four steps rather than one, soft, a bit more, more again, loud. Controlled is more convincing than sudden.

Open any piece of sheet music on this site and do it now. Reading is a recognition skill, and recognition is built by finding things, not by reading about them.