Dorian Grey - just editable polygonal object with symmetry modifier and never ending playing with poly tools like cut, ring, loop, connect, extrude, bevel, insert... All these functions are very well described in User reference in 3ds max very well. When symetrical model was done I used edit mesh modifier  to make asymetrical parts of model. There are other ways to achieve this for example, you can convert it to Editable poly again and then model asymetrical parts.

Dog - I used this reference which I found on Google... It is very important to have some references when you

create something. IIt can be very valuable when you are creating proportions of  the model.

Completed scene

faces before meshmoothing: 377 932
faces after meshmoothing: 1 352 065