Help! My sweater pattern just say "join shoulder seams". The shoulders were bound off, otherwise I'd do a three needle bind off. Is the mattress stitch my best bet? do I do it right sides together or wrong sides together? Thanks!
"Sometimes it's a little better to travel than to arrive." - Robert Pirsig
The "best way" depends upon the yarn you used and the style of the sweater. If it's a lightweight yarn, mattress stitch is fine. You do it with the right sides butted up against each other (at least I do).
But mattress stitch, while neat and almost invisible, doesn't give the seam much support. If your yarn is worsted weight or heavier, you might be better off crocheting the edges together (right sides together) or backstitching them. The trade-off: more bulk, but a firmer, more stable seam.