Inspired by Got Medieval's Google Penances, I'm going to do one, too. When I checked my blog stats some days ago, I found somebody had done a search for "tricks to faster hand sewing", thus landing on my blog. I actually had a few conversations about our modern love for speed during show-and-tell last weekend, so sewing faster by hand or concern about the length of time needed seems to be the thing at the moment.
Well, gentle reader, I regret to tell you: There is no trick. Or, to put it more precisely: There is an end to getting faster. Somehow, our modern age got obsessed with speed. Add a new machine, make a process more efficient, tune an existing machine and voilà - the process is a bit faster. Well, if you are working hand sewn seams, I can tell you: forget that. Yes, you will get faster in the beginning, when your motions for sewing are still not second nature, and of course your stitching will get more even and (usually) smaller over time. But there is a point not of no return, but of no additional speed, because pulling a needle through fabric just takes a certain amount of time, and nothing will change that. And for hand sewing - just as for many other crafts that use no machines, gadgets or automatons - there is no use in trying to push that limit.
Think of it like hand-writing, a process you will all know (hopefully): You can write extra slow for special nice characters (though that might result in the contrary, if one tries too hard); you can write in normal speed for efficient, well-discernible writing (unless you have a bad scrawl by default); or you can try to write faster, usually resulting in less discernible writing, a lot of stress and a cramped hand for a small gain in speed.
With sewing, it's the same. I once tried to sew a hood as fast as possible, just to try - it took me exactly the same amount of time as when sewing normal speed, but with sloppy, bad seams instead of the regular neat ones. And if that's not an argument against hurrying, I don't know what is.
So for these kinds of (historic and modern) handiwork, you'll just have to face it: It will take a certain minimum amount of time. You can tweak your sewing times for handsewing by not using a huge load of pins and pinning every seam before sewing (that's for machined work), but by only using one or two pins and transferring them as you progress, or basting if you need a longer stretch; by using the appropriate stitches - like not back-stitching unstressed lines of thick woolen fabric; and by using appropriate, good tools (needles) and threads (the latter not in excessive length). And after that? Face it. It takes me about 30 hours of work (not including breaks - I work with a stopwatch) to make a simple dress, about 20 hours to make an underdress, and about 25-30 hours to make a simple hairnet. A hood will typically take between 4 and 8 hours, depending on cloth, buttoning, liripipe, seam and hem finishes etcetera - something that always figures in the time needed and that cannot always be calculated exactly beforehand. I have tablet weaves where I progress a full 5 cm in an hour, due to the fineness of the threads and the pattern. And that is just the time it takes. Even if I tried, I could work no faster.
But I find that accepting this fact leads to a different view of time and of work, and it can help to calm down in our modern need-for-speed world. And that, too, is something to treasure - just like the finished hand-sewn pieces that took their time.