Random notes on sequins
This was a reply to an online question regarding how to add sequins to an item.
There are a few basic ways to attach sequins: glue (hot or cold), sewing from the hole over the edge (I usually take at least two stitches, so the sequins don't flop over) and sewing up through the sequin, through a bead, then back through the sequin. Given these techniques, pick your design (fairly simply designs like those in coloring books are good places to start), choose a technique, color, and size of sequin for each area, and get stitching!
A few refinements:
I usually separate or outline sequined areas by lines of beads. Looks sharper and more detailed.
Work on a piece of buckram, rather than directly on the item it is to be applied to. This allows the applique to be removed so the garment can be cleaned.
Overlapping the sequins fills the area more completely. When using the sew-over-the-edge technique, I will often come up in the center of the first sequin, go down on the left edge, come back up through the center, then through the center of the second sequin (from the top), continuing down at the right edge of the first sequin, up at the right edge of the second sequin, then through the center of the third sequin (from the bottom) and down through the center of the second sequin, back up through the center of the third, etc.... This make most stitches work for two sequins, which speeds things up a bit.
Recommend using waxed or other heavy beading thread, as sequins will cut through lighter threads.