1) Right sides together
2) Measure twice, cut once
3) A drawstring is made like this: half elastic, half strings sewn to the ends of the elastic. From the outside, when the strings are tied together, you'd guess they were continuous. But it's so nice to have them be half elastic, that way you can take the pants off without always having to untie.
4) Sew a thin cord inside a tube if you want to turn it inside-out later. That way you can just pull on the cord.
5) Pay lots of attention in geometry class, especially the bit about right triangles. Then again it's been YEARS since I took geometry, maybe the whole thing is about right triangles?
6) Do not spill wine on the pattern pieces
7) If you drop a pin on the floor, stop everything you're doing and pick it up
8) If you drop a pin on a hard floor, listen so you can hear where it bounces. Don't say a word. You can't hear the bouncing over a string of expletives.
9) You don't have to fix every mistake, screwup or seam pucker. It's your spirit bead... there to remind you that only God is perfect, or that minority cultures are always trying to bullshit you because you're white and ignorant. we had it coming.
10) Cut the edges of your new fabric with pinking shears if you think it'll unravel in the washer
11) Get out your scissors and trim off the excess threads. Don't rely on that little dohicky on the side of the sewing machine, it leaves a centimeter or so of length, which your grandma really detests.
and the bonus... my lesson learned, too many times:
12) ALWAYS check pattern orientation before you cut. Nobody loves a sideways bird.