ok, this is now a slight bit outdated(with how i draw), but is still able to be used well.
though, whenever i have done a tutorial, the style always comes out slightly funny, and not exactly me/usual.
and no, i do not draw directly like this, i changed a bit of it.
as it was better that way.

i start with the head of the dolphin, or what is know as the melon, in a dolphins head. then draw the eye, which is where i then did the hole in their head to breathe. i make it, so it's in line with the eye.

ahah, i love my little guy in the wading pool XD.
please do not forget his air/blow hole, or you'll drown your dolphin . haha XD.

depending the type/species of dolphin etc, the shapes, size and placing will vary in forms.

i own this tutorial.