I find myself using the 2D, background image technique the most. Where you start off with a flat square, extrude it to fit the 2D view, then start creating a rough 3D shape, and piling edge loops to give it more definition. This way I’m come to find sometimes works, but sometimes leads to a giant mess of misshapen lines.
What’s your preferred modeling technique? Which one’s the quickest? Which one gives the cleanest looking mesh?