Sewing a jacket: Any tips?

Dear users, dear authors,
Do you have any tips on sewing jackets?

The first and most important tip is, no matter what kind of clothing you’re sewing, to have yourself measured to determine the right size. That’s because the size you buy doesn’t always match the measurements on a pattern. It’s also helpful to have a dress form adjusted to your own measurements—it makes the process so much easier. Even I, who learned how to do this a long time ago, still ask my daughter (who’s also a seamstress) to check that it sits right and fits the way I cut it. It’s also important to read through the sewing instructions if you’re not exactly sure how to proceed.
Simple jackets, like a cardigan, are quick and easy to sew—you often don’t even need a button placket, buttons, or a zipper. When cutting out the pieces, make sure the pattern pieces lie straight on the fabric along the grainline, otherwise the side seam will twist forward toward the stomach over time. A seam allowance of 1–1.5 cm is often recommended; this gives you some leeway in case something goes wrong and the seam ripper becomes your best friend ;-) For jackets or blouses, make sure the center front is actually the center front; otherwise, the garment will sit crooked. On the sleeves, mark the notches—they indicate where the front of the sleeve is, since the sleeve cap isn’t uniformly round. The sleeve cap is flatter at the back and slightly steeper at the front. Don’t forget the notch at the top of the shoulder seam either—it makes it easier to set in the sleeve. If possible, set the sleeve in before you close the side seams; it’ll be easier for you—it’s rarely better to set the sleeve into a closed armhole.
At the front, make sure the jacket is the same length on both the right and left sides—so it doesn’t stick out or hang asymmetrically on one side.
Also, make sure you use the right fabric for your jacket—not every jacket can be sewn with a stretchy fabric like sweatshirt fabric or jersey.