First of all I started with a rough Pencil-Sketch to depict the basic composition and the central idea of the picture.
As you see, I originally intended to make a Seagull the 'Star', but later I decided to swap it to a Gannet. I chose to do this basically because of his long neck gave me more freedom for compositing and helped avoid the elements looking 'squeezed' into the middle of the image. My sketch laid beside my monitor all the working-time, as an orientation and recognition of the original intention to create it. Tip : Never ever dump your first sketch; it's holy.
The second step, I tried to put the sketch into 3d. Some simple 4-6-poly-objects served me as dummies to emphasize camera position, lens size, etc. At this point I often make a provisional light setup to get a first impression of the general mood. In this case; a very bright Target Directional from outside, a soft Omni from the inside and a Skylight served me as fake radiosity.
With doing all the previous set-up, I can now start with doing the real work. For the wooden beams I created a box. with approximately a square intersection which I then started to shape out wood structures with the bevel, chamfer and the soft selection-tools. (I deleted the cap surfaces because they wouldn't be seen on the final picture anyway)
After smoothing and applying additional bumps and hollows, I gave some individual structure to the surface by displacement mapping. I modelled 4 basic beams, the rest are scarcely altered versions of those ones, for I knew, that I would rework the renders within Photoshop, so I didn't spend to much time on those details.
The rest of the major walls and the roof were pretty simple modelling, again using some displacement maps gave the individual touch.