See all the tracks on the album that contains the current song:
From the Now Playing screen tap . Tap a track to play it. Tap the album cover thumbnail to return to the Now Playing screen.

Album tracksIn track list view, you can assign ratings to songs. You can use ratings to create smart playlists in iTunes that dynamically update to include, for example, your highest rated songs.

Rate a song:
Drag your thumb across the ratings bar to give the song zero to five stars.
Source: apple.com