This is a casual top with built-in very flared butterfly-wings-like sleeves. To sew this easy to make top, you need a 48 inch wide fabric which is 56 inch long. This will give you a top which is about 27 inches long
Step by step tutorial for the Butterfly top
Fold your fabric (56 inch long fabric piece, which is 48 inches wide) by half. Then fold it vertically by half. Mark the pattern dimensions as given below on this.
Mark neck width 3.5″ for a narrow neckline or a 4″ for a wider one. I have taken 4″. Neck depth is marked 1″.
The whole width of the fabric is taken as the sleeves. Mark in a nice curve, like a circle as in the picture above.
The waist is marked (B) 15 inches from the top fold. Mark H from B as 1/4 of the waist plus 1 1/2 inches.
Mark the sleeves. Cut the sleeves. Make a slit up from H to E 1 1/2 inches.
The hem is taken as 1/4 of the hip round plus 1 1/2 inches. Mark 1″ up J for a nice curve.
Cut it out. This is how it will look.
Now open up the fabric so that the front and back is brought to either side of the neck as in the picture below.
This is done to mark the front neckline differently. Mark the front neckline 2 inch from the original.
When you open it up, it will look like this.
Finish the edges of the bottom edge (hem) and the sleeve hem edge. Use a roller foot to finish the edges. Check out this post on using a hemmer foot.
For the hem I folded the edge (just the bare minimum) again and stitched with a straight stitch. I do not like the look of rolled edge on the hem. For the sleeve hem, the rolled edge is enough.
Now turn the top right side out and sew the side seams and the sleeve side seams. After you have sewn the side seams, clip the seam allowance so that the seams turn nicely.
Clip till the seam line at the junction of the seam. This is very important for the seam to turn without puckers.
As for finishing the neckline you can use a bias binding tape to bind the fabric edge. Because I am using a thin chiffon, I just rolled the edge by hand and sew the edge with a hand sewn whip stitch.