This is a wonderful trick I learned in a millinery class. It’s one of those silly things that someone shows you and you wonder why you never thought of that…. It’s simply the fastest way to tie a knot at the end of your sewing thread. I mean, right at the end, every time, without the knot slipping off the end of the thread.
Start with a threaded needle. Hold the end of the thread and the needle in the same hand, so that the thread makes a giant loop.
Grasp both thread and needle between your thumb and index finger. Hold them towards the eye of the needle. There should be about 1/4" of thread tail hanging past your thumb.
Wind the thread around the needle three to five times. The more you wind, the bigger the knot. I usually use my other hand to do this, but it's holding a camera.
Shift your grip slightly so you're pinching the wrapped thread and the needle. Grasp the needle with your other hand, and pull it as though taking a stitch. This will slide the little coil of thread onto the main thread (seen here).
Continue pulling the needle, until the thread has all been pulled through the coil. Let go of the end. You have a knot.
If your knot is not large enough, simply repeat the process. Make sure that the original knot is somewhere in the middle of the thread you're wrapping around the needle.
Pull the needle through, as before. Now you have a larger knot, because your original knot is in the middle of the new knot.