Weddingbee boards

I'm going to look at wedding dresses for the first time ever this weekend.  In Korea women almost always rent wedding dresses, so a) it is hard to find a dress to buy b) there's not a lot of choice.  My Korean is sketchy in the dress fabric/description area, so want to be really prepared before I go in. 

The problem is, I know nothing about fabric.  I'm taking this dress on a plane, so what kinds of fabric don't wrinkle very much?  What kinds of fabrics work well with alterations?  Are certain fabrics more comfortable than others (August wedding)?  What kinds of fabrics don't 'hug' the body.  I'm not model-thin....

Any info would be lovely!