General Rules For Choosing The right sewing thread
1. Color: Pick thread that is one shade darker than the fabric.
2. Weight: Match the thread weight to the fabric weight. Threads are ranked by a number system. A high number indicates a light (or fine) thread, and the medium weight of thread is a 50 weight.
3. Fiber: Try to match thread fiber to fabric fiber. Cotton fabric should be sewn with cotton thread; polyester or manmade fiber should be sewn with polyester thread. If possible, don't sew natural fibers with polyester thread. Polyester fiber is stronger than most natural thread, so over time, the stronger polyester thread can break the weaker cotton fiber of the fabric. For quilting, look for thread labeled "machine quilting" or "hand quilting."
4. Twist: The amount of spin of the thread fibers. A thread with a high amount of twist will be smoother, shinier and stronger than thread with little or no twist.