As mentioned before I am going for a dress that looks something like this:
As a result I decided to lower the neckline to more of a scoop neck and lengthening the sleeves to right above the elbow. Here is how I did it.
To lower the neckline I first used a pin to mark the lowest point that I wanted the scoop to hit on the bodice front. I used a favorite shirt to compare the neckline to.
I then folded the bodice front in half and then I used the original pattern to trace the bottom part of the scoop.
Then I connected the bottom part of the scoop with the dot on the top. This will be the actual stitch line and actual neckline once seam allowances are folded in. Now draw another line 5/8" outside of this line as seam allowance to be your cut line.
Cut the outside line.
Now to lengthen the sleeves.
Leave about 5 extra inches to the bottom of the sleeve piece.
Using a pen, draw a slightly curved line to the bottom of the fabric. You want it to almost be straight at the end since you will be folding it up to hem the sleeves.
Now cut on the line. Remember that this is still the muslin so don't be worried if it isn't perfect. Chances are it is too wide and too long, but we will take care of that later.
And here you go. Ready to start sewing.