If you wanted stars that look small and bright, then you could take a sphere, apply a white colored shader to it, then double click on the white shader and then open special effects tab in the attribute editor and then slide up the glow a bit. When you render this will make that white ball glowing, kinda what you see in the sky. If you want a fake yellow star, first model it, then apply a yellow shader and add the glow like in the first example .. hope this helped.