I used very thin t-shirt type material, so the train behind it drapes very well.  I love this pattern because it is only two pieces.  It has only a back seam and slides onto the doll as a tube shape with no side seams or fasteners.  It is only lined to the waist, although it would be easy enough to line the entire dress.  The top of the bodice is elasticated so it stays on the doll snugly.

The shawl is a piece of lace I joined into a tube using a French seam.  See how to put it on the doll in the image below - easy peasy and it looks very dressy.  The belt was made by sewing buttons onto a piece of grosgrain ribbon, then adding snaps to fasten it at the back.
.
This is a long dress adapted for Barbie from a free Tonner gown pattern by
© m.dita 2009 I found on the Internet