From FM Quilter Monica Pavek, she advises that if you’re having a lot of difficulty threading your needle flip it over and try threading through the other side. During the manufacturing process, the eye is punched out leaving one side slightly concave and the other side slightly convex. If the thread won’t go through one way, you might be trying the convex side and you may have an easier with the concave where the eye is shaped very slightly like a funnel. It’s a very small difference that you can’t see with the naked eye but it makes a difference in the ease with which a thread will go through the hole.
She also brought up the old trick of licking the eye when it’s being stubborn. The minute amount of saliva can ease the thread through.
Other advice is to clip your thread at an angle so that the end of your thread doesn’t splay out.