First off, the way I quilt with jeans is not the only, best, or even the "right" way. It's just the way that has worked for me.
That said, I've done it often enough to make lots of dumb mistakes and learn from them. So I do recommend you learn here -- not the hard way!
Check for Smells
If you get jeans from the thrift store or some other nefarious source, check for cigarette smoke smells. Why waste time on stinky fabric?
To store blue jean fabric, cut out each "panel" and throw away the "skeletons." Fold the denim neatly and store it in a cardboard box or plastic bin. I use empty Deli-Cat plastic buckets.
Before cutting pieces for the quilt, press the denim for more accurate cuts. (Note: "Pressing" means to iron the fabric without moving the iron back and forth; just blot and lift, blot and lift. Otherwise you'll distort the fabric, which may cause crooked cuts.)
Plastic is Painless
Do yourself a favor and get some shallow, see-through plastic drawers for your sewing area. You can put quilt pieces, unfinished blocks, unbacked tops and scraps in separate drawers. This keeps everything organized and minimizes fraying. Plastic drawers are also great for storing sewing accessories.
Possible sources for plastic drawers are Wal-Mart, Sam's Club, Costco, Office Depot, Home Depot, Lowe's, and similar retail stores.
Cut the biggest quilt pieces first. Nine-patch blocks can be made from three-inch scraps, but star quilt triangles must be cut from 7-7/8" squares. Tip: The back half of jean legs is usually wider than the front half. Cut the 7-7/8" squares from there.
Do save the muslin-like front pocket linings, the back pockets, and any scraps bigger than three or four inches square. The front pocket linings can be made into quilt labels. Four-inch squares from scraps and pockets can be used in a Scrap Blocks Blankie. Three-inch squares can be used in a Roads and Rails Blankie.
Scraps smaller than that are useless for quilting. Throw them away.
What's Not Worth Saving
Avoid using the knee fabric. Even if it is not torn, it is usually faded and stretched out of shape. Pieces cut from this area will be distorted.
Throw away any denim that is stained, scuffed, torn or worn thin. You will be putting a lot of time and effort into this quilt, small as it is. Make sure it looks nice!
Don't bog yourself down saving the zippers or jean 'skeletons' (what's left after the panels are all cut out) unless you truly have a use for them. They'll just breed in the closet. Throw them out!
The best backing fabric for denim blankies is polar fleece. It is attractive and easy to work with. Just don't iron it! It will melt.
Blankies can also be backed with terrycloth or bath towels. These fabrics are too thick to bind with, so I'd use them only for the Quick Turn method. Also, the little cotton loops will catch on the sewing machine's foot prongs and feed dogs, so they're harder to work with.
Denim, polar fleece, and terrycloth are all thick fabrics, so batting is usually not necessary.
Since you must usually buy the backing new, it's often the biggest single expense of making the quilt. If you can catch a sale on some nice polar fleece, wonderful! Buy extra. Home Fabrics sometimes has bolts of discounted fleece for as little as $3 a yard.
An ordinary rotary cutter is nice for processing small scraps.
A 4" plastic quilting square is handy for cutting out back pockets. Check smaller, local quilting or sewing stores. Wal-Mart may not have any.
For accuracy, a Fiskars 24" rotary ruler is a virtual must. (The one in the picture uses a 45mm razor.) Denim is thick. An ordinary cutting ruler will invariably slip to one side and spoil your cut, plus a fair amount of fabric. Arg!
A large cutting mat is essential. Wal-Mart seems to have the best prices. Get one that's at least 17"x23", and make sure it has a handle so you can hang it on the wall.
If you have any choice at all, cut out your quilt pieces on a table. Cutting on the floor will make your back hurt. Make sure the table surface is level, or you'll wind up with partial cuts. Hollow plastic tables, especially, tend to have saggy spots.
When attaching the backing fabric, you'll find that a walking foot (or dual feed foot) makes wonderful pucker-free seams. If you are going to make more than one or two jean quilts, it is well worth the bother of tracking one of these down. There are different types, so make sure to get one which is compatible with your sewing machine. Expect to pay between ten and thirty US dollars.
Large safety pins are terrific for holding backing fabric to the quilt top during sewing. Unlike ordinary pins, they will not catch on everything in sight (including you). These are about 1-1/2" long. Save a small Tupperware bin or a metal cookie tin to store them in.
The Work Space...
Make things easy on yourself and store everything accessibly. Hang cutting mats, rotary cutters, rotary rulers, and other large flat quilting accessories on nails or screws, close at hand so you can easily take them down and put them back. This frees up table space and makes setup/cleanup a breeze.
Ready for more? Learn how to make a Hope Star Blankie. (Photo Intensive!)