Hi, I'm new but I think I can help. I have her Plaits video (I don't recommend buying it because it's not very thorough and shipping takes a long time). She shows how she achieves this look. Use "kanekalon" hair, cut it to whatever length you want to use or leave it long if you want braids long like hers, take the amount of hair that you're going to use to make a single braid, hold this in the middle with the ends down so it looks like the letter "n" then use the thumb and index finger of your free hand pull the ends a little until they look thin and scraggly (is that a word?)-(do this to both sides); it's called "stretching" the hair I think.
Put the braid in your hair and braid down to where you can't really braid anymore because when you get to about an inch or so from the end, you'll find that you can't really comfortably continue to braid because the ends have gotten too thin (see how her ends are very thin?). I think you'll see what I mean once you make the braid. When you're done braiding, just dip the braids in hot water for about three seconds. Don't dip too many braids at once because for some reason that'll lead to tangling (she says this on her video too). After I did my whole head, I dipped my braids in the hot water in five sections to prevent tangling. HTH