[Stiglr]

I'd start with some web research: assemble a bunch of good photos showing the killer whale from all kinds of angles. Then use that to model from. Even better, look for an "encyclopedia" type of illustration that might show it from a direct "side angle"

I'd say an orca would be based on a basic cylinder shape, with the flippers and tail added onto it. The appendages could be done using basic box modeling techniques.