Seaming cast-on and bind-off edges:
When working a seam, it is important to think about the purpose of that seam before deciding upon the best way to close it up. For example, the top and bottom seams of the Fair Isle Pillow have been sew together over the bound-off and cast-on edges. The bound-off edges provide for a strong, stable support for the pieces to be seamed together. This method is also good for jackets and heavy sweaters. The photos below show how this type of seam is worked. Remember, it may take a couple tries to get the stitches lined up and sewn together evenly. Practice makes perfect!
Another way of seaming is to leave the stitches live and then graft the pieces together. Although the seam is much softer and less obvious, it is also not as strong and the stitches are more likely to stretch under the weight of heavier garments. When working the shoulders on a summer garment in a lightweight yarn you may prefer to keep the shoulder stitches live and graft the shoulder seams together for a smoother, less visible seam.