You can do it in a number of ways.
I place textures over the renders and erase them over the main part but leave them over lapping the render's edges and set it to lighten, screen, darken or something like that. Some people like to erase the edges of the render to blend it in a little, whilst...
Not bad mate.
Make the colours more dynamic and add soem lighting. I would burn the edges as well.
I think that's all it's missing.
Nice job otherwise.