The dress is made up of four parts; a circle skirt, a waist band and two long straps which are all sewn together along the same seam (the way I did it at least!).
To cut a perfect cirle, first cut a perfect square from your material. Fold it in half to make a rectangle then in half again to make a square. Tie a pen to a piece of string and hold the end of the string on the corner of the square that would be the centre of the square then trace a curved line from corner to corner. When you cut along this line and unfold the material it will be a circle. Cut a smaller circle while the material is still folded for the hole in the middle. To figure out how big to cut this circle use the length of the waist band you have created ad the circumferance and then divide by 2 and divide that by pi and you have the radius which is how long to make the string when you draw the curved line.
I lined the straps of my dress by sewing two identical pieces together in a tube and closing one end and sewing the open end in to the seam of the dress which
worked really well. It makes the dress a little hotter but creates a nicer finish. To make a nicer seam just cut both halves in one piece and fold in half then sew and sew the folded seam so that it is the side in the middle of the dress. I recommend sewing the waistband into a circle first, then fold it in half, and pin it in quarters around the hole in the skirt then sew these two pieces together. Then make sure the seam of the waist band is at the back.
Then sew the two straps on to the seam you have already created on the inside of the dress with a slight overlap.
The dress is pretty much finished unless you want to hem the skirt. I haven't figured out a good way to hem the skirt without it making it bunch as it is cut on the bias. Mum suggested using bias binding to sew a hem but the binding makes it a bit stiff so I haven't hemmed my dress YET. I will wear it out without a hem but eventually I want to hem it so please post your suggestions on how to hem it! I don't have access to an over locker so that is ruled out unfortunately :(