Oh man, I'm glad that's workin for you! I tried that a few times a while back when I saw it on tumblr, but if your vanishing points are really far away, there's too much space between each "line" of the star for me.
I just extend a couple lines of my rough sketch to figure out where the vanishing points are, then set two guides to intersect over that point, set my line tool so that it snaps to guides automatically, then just drag a bunch of lines towards the vanishing point!
also, since we're talkin' about it, here's my favourite guide I've ever seen for tackling perspective for anyone that's useful for! I think fancy tools to draw perfect grids aren't super useful if you don't have a solid feel of what that grid is indicating, so Jake Wyatt's tips for getting a feel for perspective without worrying about rulers struck me as a good place to start.