I found needle threaders, even those sold in beading stores, aren't fine enough to fit through beading needles easily. I broke mine on the first try.

Search YouTube for videos on how to thread beading needles. There is a trick to it, and once you know it, it is much easier. You also need very good light and magnification.

If your project doesn't need really small needles, you can also use big eye needles, which are split almost all the way down the length. You pry the two side open with your fingernail, and it's easy to get the thead through.