Then I used a staple gun and some kind of landscaping string to make a 1 ft x 1ft grid on the ceiling. I figured this way, the room is 12 x 10, which is 120 sqft, and there are 600 strands, that gives me 5 stars per sqft. I tried to drill the holes randomly, but the grid helped me maintain a pretty even layout.
a much easier alternative is to use glow-in-the-dark stars you affix to the ceiling with poster glue. or just straight glow-in-the-dark paint. you'll get the star effect for awhile, then they'll gently fade as you fall asleep.