I learned something new about threading needles this past year. It really works.
Wet the BACK of the needle eye. You no not have to wet the thread. Most of the time I don't even have to re-cut the thread. If it doesn't go through first time every time, then try making a fresh cut on the thread. Works on hand sewing needle and on sewing machine needles. Of course you have to be able to aim your thread in the general direction of the needle hole. LOL