Twinset Style

This is probably the most complex of these designs, but it's not super hard. If you decide you really like this style (and you hate my directions for assembly), seriously consider buying Elizabeth Lee's twinset and more pattern #307. She has a really clever technique for constructing the jacket neckline. My way works, but her way is better.

Decide how low you want your jacket front to go. Measure some of your v-neck clothing to see what depth you like. Then mark the correct depth on your pattern piece.
Whip out your handy ruler and connect the depth mark with your shoulder line. Ta-da! You've just created your jacket neckline and your pattern should look roughly like the drawing below.

Remember to include a seam allowance for the center front of the jacket when you are cutting it out! Or create a facing for the neckline and front edges. It should be about 2" wide, though you can make it wider if you'd like. You'll need to face the back neckline as well if you go this route.