Been there many times and I hate it. Some commercial sewing pattern instructions seem determined to make things as difficult as possible. Unfortunately these difficult to sew areas then make your garment look home-made rather than beautifully crafted.
Here's a principle that cuts down on some of those problem areas: If in doubt work on the flat piece first.
Plackets, zips, pockets - what's the point of closing the long easy-to-do seams first and then do the fiddly bits? I just don't get why some sewing instructions do this the difficult way around.
You don't need to stick to the order suggested.
Look at what features your garment has: double-ended darts, zip, plackets, pockets, pocket flaps, collar etc, etc? These are really nice sewing exercises (as long as you don't let the instruction sequence make your life more difficult).
Once you've cut out your pieces and overlocked what needs overlocking* - do all darts first before you sew anything else. No side seams, no nothing else. The sewing instructions usually start with this too, so no problem here. (The only exception I can think of is if a dart needs to meet another dart exactly: then it is much easier to close the seam first and sew the two darts as one across the seam. Anything to make life easier!)
*: But sew darts that end in a seam before you overlook the piece: less bulk when you take a single pass with your overlocker over the sewn up dart avoiding three layers of overlocking.
I used to hate having to do zips, now I like them more and more. Sew them in first!
Don't even close the seam underneath yet (a lot of YouTube videos show it this way too so you're in good company), sew the zip onto both pieces and once you're happy with it close the seam underneath (make sure to off-set this line by a millimeter or so to avoid the pucker at the bottom of the zip).
Same thing for plackets on sleeves: sew them in before you attach the sleeve or close its side seam (a very good placket article on Threads shows it that way too).
Patch pockets: why go to the trouble of working on an almost assembled item when it is so much easier to sew a pocket onto flat fabric. In-seam pocket bags are also easier to do before you close the longer seams: a) attach a single pocket piece to one outer piece and b) the other pocket layer to the other piece - then c) sew the pocket layers to each other, and d) close the seam of the outer garment above and below the pocket opening.
I would attach a collar as soon as the shoulder seam is closed, before any other seam stitching.
Depending on the shape of a sleeve it can be easier to sew the sleevehead to the front and back of the garment before closing the side seams of body and sleeve - this is easier for wider, more relaxed styles. Sleeves that are quite tight and where the sleevehead needs to be eased into the armhole are better done after closing side seams.
Flat pieces are easier to manoeuvre and allow better accuracy. They are also easier to press (best sewing tip ever: press, press, and press again!).
Once you have these kinds of elements done, the rest of the garment is much easier to assemble: nice long seams that pull everything together. After that you are left with things like neckline bindings and hems that need to be done across all closed seams. Couture houses work this way too: everything is done flat until only the long seams and hems are left over,
What do you think? Is this useful?
