Remove any selvages from your quilt backing before piecing. The easiest way to do this is to make a little cut just below the selvage, grab a hold of it, and just rip it off – this will leave a perfectly straight edge.
If you’re making a quilt with pinwheels or similar intersecting points, try to press the seams open when you’re putting the top together to flatten them out. This prevents the longarm from encountering big lumps and having the stitches not stitch properly.
Be sure your quilt is as square as possible, and any borders are completely flat. Press the backing and top. Don’t worry if your batting (if you are supplying your own), has a few wrinkles in it. I found that generally irons seem to stick to batting, but I have a European dry steam iron that does wonders on it.
Make sure that the top and bottom of the backing are straight – these are the parts of the backing that are pinned to the cloth leaders on the machine and that helps make sure everything is straight.
It’s good to have your backing and batting at least 3″ bigger than your top, on each side. The machine needs some extra room on the top and bottom and the sides have a little bit of “takeup”.
Special Note on Borders:
When attaching borders, you want to make sure that they don’t end up “wavy”…that is to say that your borders are longer than the side of your quilt. The most common way this happens is to sew the border onto the quilt without pinning or measuring, and just cutting it off on the end.
1. Take 3 measurements of your quilt – top, middle and bottom. Take the average of these and cut your border to that size.
2. Lay your quilt on a flat surface, and pin the border all the way down, making sure it’s flat and the borders don’t pucker, then sew and cut off at the end. This works best when not using mitered corners.