When I was satisfied with the overall shape, I started to model some details. The first one was the tail or better his back fin.
Sorry I forgot to take some shots the between image on the left and the image below. You'll have to imagine those.


Do not wait to finish the model before you apply the meshsmooth modifier. Apply it during the process of making Sharky to see where are you going. And do not remove this modifier either, just go to Editable Mesh and turn off show end result by pressing the button. Now you can work with Editable Mesh and see the smoothed result simply by clicking one button. That can be very useful.

Here is a smooth look of his back fin. When you add a meshsmooth modifier the model shrinks a bit so make sure that the non-smoothed model is a little bit bigger in volume.


Note that there is an edge running along from the head end of the model all the way down to the end of the back, the joint of the back fin. I doubled this edge to mark the area where the back of the shark ends and the flanks begin. Later the back should be of a darker color than the belly.


The next step was to model a nose hole. This was easily done by adding (cut tool) more edges. Follow the images below....
 


Delete the faces where the hole is going to be and extrude the edges to the inside of the model. 

Select all edges around the hole, press and hold shift and move them inside.


Now to see how this looks when smoothed, press show end result in the modify panel.


Next step was to create a hole for the eye. The eye will be a sphere in this phase. In side view position it and lock the eye-object.  Make some cuts into the shark's body similar to those at the nose hole. The process is the same.



And again move the vetices up and down, left and right till the eye hole fits the eye.  Go to the eye's properties and check see-through. It can be useful to see better.
 

Here you can see the finished eye- and nosehole in another beautyshot of the smoothed model.