*mind seam allowances!!
Width: Usually either full width of fabric or half.
Length: From shoulder to at least knee.
Skirt gores: About half the length and as wide as you like.
Sleeves: Loose around arm unless last quarter of century, then comfortably fitted. Gathered to armscye. Should reach past elbows comfortably.
Sleeve gores: About 4"x4"
Neck hole: Leave at least 4" of shoulder and the back should be 3" above front. Best to mark on you keeping in mind it gathers up later.
Neck ruffle: Optional. The best formula for length is 1.5 times and about 2.5 inches finished.
Once you have the pieces cut, assembly is fairly simple. If you aren't trying to be completely accurate you can finish the edges and seam it all together. Otherwise take the time to french seam, flat fell, or use a mantua makers stitch (right to right edge and fold 1/4" twice then slip stitch through both layers). Around the neck you will make a channel using twill tape. Either fold the ends under and butt them CF or stitch two small eyelets CF. If you decide to add a neck ruffle, here would be the place to stick it in. The sleeves give you options as well. Assuming you have looser sleeves you can place the channel at the end or add a 1/2" wide buttoned cuff. You'll finish the hem and possibly raw sleeves with a roll hem.
Here is an image of the shift I made:
Notice the differences between it and the pattern I drew? First, mine tapers at the body top. My fabric was wide enough compared to me that I was able to cut the gores from the top half and apply them to the bottom. Perfectly allowed if you want to save fabric and have enough width. My sleeves are fitted tighter, so they aren't gathered in. I also have shoulder seams.
Since this is my first experience with instructions, please feel free to give recommendations or talk about problems. I'm sure there's something I missed!