One of the annoying side effects of improvisational quilting is the constant starting and stopping when you sew. Depending on your plan of attack it might be difficult to chain piece. That can leave a lot of cut threads, mess, and wasted time. A good quilting friend of mine taught me this trick.
Take a scrap of fabric and double it up (or use two small pieces). When you finish a seam, sew a a few stitches in to nothing, then sew in to your scrap. You can then cut your piece from the scrap without a tangle of threads to deal with. When you come back to your machine for the next seam just sew from the scrap piece, cutting it off when you go to press.
I usually keep two of these by the machine. One for the start of my sewing and one when I finish the seam I'm working on. That way you always have one handy to plug in to the end of your seam when you leave the machine to press.