Preparing Your Quilt
There are many great books, classes and on-line tips out there for preparing your quilt top and backing for long arm quilting. Here are a few tips I have gleaned over the years that will help you make your quilt look great!
Adding Borders:
A lot of quilters just sew the fabric to the sides without measuring (I am guilty too). To get a border that isn't wavy you need to measure the average to ensure you get an even border.
The quickest way to do this without hauling out the measuring tape is to spread your border fabric across the middle of the quilt. This area has less distortion than the edges/ends so you can contain your quilt top easier.
After you cut the border to the middle measurement, pin it from the center of the edge and out from there. You don't need a lot of pins - I get by using about half a dozen.
Pressing
You all know the rules about pressing towards the dark fabric! Another area to consider is the junction of seams. If too many seams meet in one place you will get a hill that we can't quilt out. Try taking a couple stitches out of the end of the seam so you can spin or rotate the seams to help them lay flatter.
Threads
All quilts end up with those squiggly little bits of thread. Take the extra couple minutes to snip them off during your final pressing (you are doing a nice, final pressing before packing it up, right?). Sometimes we see the threads too late and they end up as a "design element" in your quilt because the threads become very stubborn to remove once quilted over.
Preparing the Backing
Long arm quilters need extra fabric to grab on to when loading the quilt on the machine. This ensures the quilt has proper tension and gets nice, even stitching.
This is one of those times you do have to haul out the measuring tape. Measure your quilt top (you'll need that information for the form anyway). Make sure you make your backing at least 4 inches longer and wider than your top. The batting should be at least a couple inches longer and wider than your top.
It is important to have your backing fabric on grain. This prevents odd puckers and shifting that we can't quilt out. The easiest way to get your fabric on grain is to rip it instead of cutting it.
The seams on the backing should be one inch deep and pressed open with selvages removed. This keeps the seams laying nice and flat so they won't show through to the front. When you are sewing the deep seams, trim off just a hair (1/4 inch or so) of the selvage since that edge doesn't behave like the rest of the fabric - this avoids ripples in the seam.