So there are some shapes / pattern pieces that can prove to be a little challenging to get just right:
Armholes are one of those shapes.
Let me show you an easy little trick!
1: Depending on the size of the armhole, place three or four pins into
the seam allowance.
2: Cut the other areas of the garment leaving the armhole until last.
3: Cut out the armhole from TWO directions, either from the underarm or shoulder to the notch marking. Repeat in the other direction.
If you follow this quick and easy tip, you’ll minimize any movement allowing for greater accuracy when cutting curved shapes such as armholes.