Doll Clothes

This might have come up before but I can't be bothered looking lol

If I make something should I cut the fabric a cm or more bigger then the proper measurements and should I use a very close and neat running stitch along the shape of the fabric (have to do it by hand don't have a sewing machine) so that when I turn it the right way the shape will be exactly as the shape of the running stitch? I hope that makes sense. I just did a practice dress and it was awful lol. It's hard to figure it out in my head but for the straps and neckline should I seam them first and then sew the rest of the dress together?

Thanks x