So I started out sketching monsters but then got derailed by twiggy bird legs so I ended up doing this grumpy bird instead of a proper monster!
I sketched on paper first, then moved into Photoshop for more sketching once I decided on my bird. Here's my first rough version of him shrugging:
From there I created the more polished version of him shown here (with a background inspired a little by Jake's example):
And here he is waving!