:XX: How do you seam the arms if they have decreases and increases? Its hard to tell where to do the mattress stitch on the decreases and increases… 
AmyC
It is hard. I usually try to go in one stitch in from the edge as best I can.
It also helps if you don’t do the decreases/increases right at the edge. Even if pattern say to, I always do the inc/dec two stitches from the edge, then you usually have a nice clean line of plain stitches for seaming along the edge. I agree though, seaming in sleeves can be challenging at the best of times.