The Canvas : Step one.

After adding gradient + noise

Draw a circle using eclipse tool, and then the tail using pen tool. merge them together.

Draw the eyes using brush (first white then black inside, then again white to give eyes some realism) also adding some dark color to the previous shape.

add the smile, using pen tool. you could also use clipmask for perfection

polish the smile using brush tool.

remember the layer where you added bright colors right? go ahead and play with the blending mode.

Copy the layers(or the entire group) and resize!

The final Slide, add cirlcles (three shades) and copy that all over. make a pattern out of it. try to make it look like bubbles. !! TADA YOUR DONE within few minutes :)