Most of my tips would be from Bernadette Banner and Abby Cox videos, but I think one of the biggest from those is using good needles. Abby goes over how important it is to have decent length needles with smooth eyes, i.e. not the kind you'll find at Joanne's. Needles from England and Japan seem to be of the best quality, and the eyes are larger and smooth, which make them easier to thread. One gal uses embroidery needles for sewing, which are longer than sharps and thus can be easier to handle.
Burnley and Trowbridge is a site with really good thread, including old-fashioned 2-ply. Abby suggests using only strong, smooth silk or linen (the linen always needs to be waxed, but it's generally the only thread that does). I've read/heard that keeping a shorter length of thread, only about one arm's length, makes it easier to handle and less likely to tangle. I'll eventually try not even cutting a length and just sewing straight from the roll, because I'm curious about it and the method I use doesn't require knotting the thread, it's just a single layer rather than doubled.
A recent video I watched (from Bernadette Banner, her newer "I sewed a pirate shirt" one) mentions that before the Victorian era, the stitches weren't as small or neat, because their attitude was more "get the job done" than "make it pretty", and since I'm hoping to one day sew a full wardrobe for myself I think I'll follow the 1800's example instead of the Victorian, because I know I won't have patience for 2mm back stitches, haha. Just a reminder that Victorian manuals are probably going to be really strict about stitch sizes, when it's not actually necessary.
