This was one of my first projects, took less than an hour and very little sewing.
I had 1 metre of 60inch fabric which was on sale at my local fabric shop.
-Measure yourself from top of shoulder to ankle and trim the fabric to size, allowing for hemming. I just took a few inches off the bottom, so I had (roughly) 1metrex55inch.
-Hem all four sides.
-On the top, sew a tube that will later be wide enough to thread 1/4inch elastic through (blue)
-Hold the fabric around you, the top corners over one shoulder to decide where you want your arm hole to end.
-Sew the two sides together (red) from your arm measurement down to where you want the slit to end (mine was mid thigh because I stride rather than walk, so I needed plenty of room)
-Measure around your chest, from under one arm, over the opposite shoulder.
-Subtract an inch from that measurement and cut 1/4inch elastic to fit.
-Thread through the tube at the top of the dress.
-Sew the top corners and elastic together.
-(Optional) Add some form of decoration to the last join, I added a large button as I wasn't particularlt neat.
Wear with a wide belt and you have a lovely summer dress