Originally Posted by katesnanna
The VERY best tip I ever got was to use 2 pins when lining up seams. One on either side of the seam. Providing I have it properly lined up before I pin it won't shift and has saved me lots of unstitching over the years.
To add to this, first pin horizontally about 1/2" above the raw edge. Then flip the top up and make sure the seams match. Make any necessary adjustments, then with the horizontal seam in place, pin vertically on either side of the seam. Then remove the horizontal pin. This also works really well for paper piecing - pin along where you would sew - along the seam line. Then fold the fabric over like it would look if it were sewn - you can make adjustments BEFORE you would have to rip out the seam. Also, when doing a new paper piece, first sew with a larger seam so it can be removed easily if necessary. If the first seam is correct, go back and sew with smaller stitches so when you remove the paper, it doesn't stress the seam. Either that, or remove the thread from the machine needle so you aren't sewing an extra seam, yet you are putting extra holes in the paper so it's more perforated for easier removal.