As of today I am half-way done with channeling and basic assembly.
I'm assuming if you're using a pattern that it has markings for casings. If it's fully-boned there might just be directional arrows, but that's all you need really. Working on a dark fabric you can use a light colored chalk pencil, on lighter tones a pencil works fine (just don't make the marks too heavy). I always plan out on my paper pattern first. For fully-boned you don't need to mark out every casing, just find the center one. If it's like my pattern, you may have to adjust spacing or even add a couple channels to fill it in properly. I didn't adjust much, so mine simply angled a bit more or moved over. Keep in mind that your channels need to be just slightly larger than your bone. If you're working with splints, you'll cut them to size so it's not as important. I'm using a mixture of ash splints and spring steel, so I had to adjust some of the channel widths from the original pattern to work with 1/4" steel. They were all about 3/16" to begin with. Once you've patterned and marked out your lines it's time for the long part.
The first thing I want to say is to beware of creeping linings. The two linen layers will shift in the direction you are working, be it up to down or right to left. In order to prevent the discovery of an inch of extra lining there are a number of things you need to do. First, pin baste. I usually scatter them around running with the boning. In my case, I put them between the casings in the open spaces. When you are working a row, put a few horizontal pins in every couple of inches to keep it from shifting that direction.The other thing that helps drastically is to jump around the piece. I did two rows on the very side, then jumped to a middle row. Doing the other side next makes sense, but since this piece has partial lacing, I'm going to have to fold the edge under first and that is what really pushes the lining around. So, I'll probably do one more row a little closer to the center first. In this case, the first, second, and third rows will go through folded layers so I'll wait on those.
All of the rows will be done in a nice back-stitch about 8-10 stitches an inch. For those of you less used to period stitching, no knots. Start by burying the tail and then make a couple of small stitches over the exit point. Knots make it too easy for the thread to pull through (take this from someone who repairs other peoples hand-stitching for a job).
Even though I already talked about the process of folding under a lacing edge in a previous post, I'll cover it again. You'll want to trim the inner most layer of lining back just past the basting stitch. It helps reduce bulk for the eyelets as well as help with a shifty lining. Also, make sure you leave the edge channel a little wider since it curves over the edge. I stitch the first two rows through the 5 layers, trim the other lining away and do one more row with the fashion fabric. When you put the loose lining in at the end, it will fold under before the eyelets so you can replace it easily.
For eyelets you'll need an awl. Whatever you do, don't punch a hole in the fabric. An awl just pushes the threads out of the way and prevents it from fraying later. By doing this you can use as many stitches as you like. I've seen extants with only four stitches holding an eyelet open. I prefer enough to cover the inner edge. My fronts have parallel eyelets, but the backs are set in opposition for spiral lacing.
Now, it's not an issue in all patterns, but mine has intersecting bones in many different locations. You'll more often see a horizontal bone doing this, but this pattern overlaps some of the bones coming up from the tabs to keep it from flexing. Obviously, you can't put two bones in the same channel or they would rub. So, you add a lining "patch" on to the inside. You'll place one of the bones one layer further down.
The hard part is not stitching across the original channels. I usually stick a temporary bone in so that I can stitch from the back without worrying about catching the top two layers. I also have three horizontal bones patterned in, but they all stretch across the seams, so I'm going to wait until near the very end of construction to put those in.
Once you've stitched all you channels (I'll see you in a few weeks), you'll need to assemble. For this, you'll fold back all of the seam edges and baste them. Make sure your outline basting stitch is centered on the fold. Note: NO trimming any linings here. Place your pieces right side to right side with the edges up. I usually place two or three pins to make sure my ends line up. You'll whip across both pieces, making sure to go deep enough to catch all three fabric layers. I do a few overlapped stitches at top and bottom since those get the most stress. About 10 stitches per inch (or a bit more if you want). Don't stitch too tightly, but make it snug. Once you've finished the seam you can gently unfold it and pull it open to flatten it out. There should be no gapping between pieces. If you have a lot of excess fabric you can trim away a bit, making sure to leave at least 1" around all edges.
At this point you can fit again, then fill in the boning.