1. Begin by seaming the skirt gores to the body. This can be done as a normal seam or as a flat fell.
2. If you have shoulder seams, stitch those together here (seam or flat fell). Stop 5" in from edge.
3. Next you will fold along the shoulder seam and stitch up the side seams. Stop where the gore will begin. Figure this measurement by adding the finished gore measurement down from your arm pit. On me it comes to about 10" with a 4" gore, but I'm fairly small. I probably wouldn't put the bottom point of the gore below the bottom of your bra. Use a french seam or mantua makers stitch if hand sewing.
4. Stitch your gathering lines on the sleeve head stopping at the seam allowance.
5. Stitch the sleeves into a tube leaving the finished gore measurement plus one seam allowance open at the end. (French or mantua) If you are cuffing the sleeve, leave 2" open at the other end as well, then roll that 2" and whip down.
6. Attach the gore to the sleeve. Mark the stitch line corner on the gore to get it matched well. (French or mantua)
7. Next you'll attach the sleeves to the body. It's best to mark out the top center on both as well as the location on the body where the gore/sleeve seam should be. Gather up the sleeve head evenly to fit the space given.
8. Now it's time to fit. Cut a small hole just large enough for your head to get through at the neck. If you have a shoulder seam you can curve the opening slightly. Try to keep the curve close to the center just in case you want more shoulder seam sewn up later.
9. Draw a rough neckline remembering it will gather up later. I usually place the CF bottom between bust point line and underbust. Back is around 3" above front. Clean it up after laying it out again and cut open.
10. At this point you can finish off the neckline a couple different ways. Your two options for the channel are cotton twill tape (1/2") or bias tape. Twill tape is more accurate of course. If you are choosing to stitch tiny eyelets in the CF do that first, if not, fold the ends of your tape under and butt them together CF. Stitch your ruffle between the tape and the fabric, or make it "removable" and place it on at the end.
If using twill, stitch it to the right side of the shift with a 1/4" overlap (more if you think you need it). Fold the tape to the inside and stitch (back stitch) along both sides of the tape.
Bias you'll open and stitch in the ditch with right to right edge. Fold the tape and stitch along both sides of the tape.
The stitching at the top of the tape keeps the gathering tape from wearing at the linen.
11. If you are placing the channel at the end of the sleeve do it just as the neck. If you're doing a cuff, cut a strip of fabric 2" wide and comfortably long enough to go around your arm (including overlap for button). Fold the strip in half length wise, and fold the edges in again to make 1/2" bias tape (don't cut it on the bias) and fold the ends inside as well. Gather up the sleeve and insert it into the tape. I'd recommend a spaced backstitch here. A very small buttonhole about 3/8" from the edge and an equally tiny button will finish it.
12. Finish the hem and possibly the sleeves with a roll hem.
13. Run a 1/4" twill tape through the channels and leave enough so it won't disappear. Make sure to tie a knot in the ends so they won't unravel as much.
Congratulations! You should have a finished shift at this point!