The roof is wrong... It should be pitched all over, most roofs do not pitch in both direction, or if they do it pitches more in one direction that the other.

Likewise look at the location of the chimney, that will start against one wall of the hut, so it needs to come out of the roof at the right place.
Your hut has no windows.
What is the scale you're working on? If the door is around 2 metres tall (6ft ish) then the hut itself is only 2 metres wide so only has 4 sqaure metres of floor space.
Likewise this means your chimney is around a metre wide.
Those are just my first thoughts, it's a good start though, but think about how this will actually work and scales of things.
Use the google image search to find references, I found this which may be of use.
http://images.google.co.uk/images?hl=en&lr=&q=hut&btnG=SearchThis looks like pretty good reference if you use the up and down arrows there's plenty of examples of buildings, these are 3d models anyway.
http://www.f-lohmueller.de/pov/im_a72.htm