Setting the scene

The ground is a plane with a sand bitmap applied to it and the sky is a bitmap placed in the environment slot. The sea is a box with a multi sub-object material applied where one is the water and the other is the foam of the breaking waves. This will not be animated.

There are no rigs in these models yet, so these are just test renders to get the idea of the setting across. This first shot is the crab first noticing the seagull and his rather fancy hat.

Here is a shot of the crab closer and he has a menacing grin on his face. The seagull is looking away, oblivious to the crafty crustacean. Using the look-at constraint allows the eyes to be positioned right at the hat. The eyelids are pulled closer together and combined with his grin, makes him look suitably mischievous. 

Here is a higher angle of the same scene, but with a very basic box-modelled boat just to create more atmosphere. 

A daylight system was used for these scenes with mental ray enabled which makes it look brighter and more lively. The sharper shadows behind the boat created by the daylight system make the sea more obvious as being flat, but this very minor issue is not the focus of the task anyway.