Check out Burdastyle.com its a great site with a decent amount of dress patterns that you can get for free. I would definitely check used clothing stores as well, since you can get some great dresses there for cheap and embellish and cut as you please :)
by Jessica G.
Also, I'm not exactly sure what a babydoll dress looks like, but Ninjatoshiba on livejournal has some great tutorials and one of them is for this insanely cute dress that may be a baby doll style.
you have to scroll down a bit to get to the link to her tutorial, she calls it a bubba dress. also you will need to message her to get a password for her tutorial site, but she loves to share her tutorials so its no big deal. She made it private because some other girls were harassing her on her site.
I find a staight stitch to be the strongest, a zig zag stitch is mostly for stretchy materials like jersey. You will need a stronger thread and a machine that can handle heavier materials. I would go to your local sewing store, the people who work there really know their stuff and should be able to help you pick thread and everything.