For each star you will need the following:
(8) 4.5"x4.5" colored squares
(1) 4.5"x4.5" white square
(8) 2.5"x2.5" white squares
Draw a diagonal line across each 2.5"x2.5" white square.
Place one 2.5"x2.5" white square on top of one 4.5"x4.5" colored square. Sew along the marked line.
Trim 1/4" away from the sew line. Press.
Place another 2.5"x2.5" white square in the opposite corner. Sew along marked line.
Trim 1/4" away from the sew line.
Press and repeat to make four. These are your star points!
Arrange your pieces as shown below.
Sew together into three rows.
Join rows to complete block.
I used 12 fat quarters for my Stargazer quilt. The finished quilt measures 48"x72". If you use the full 18" of your fat quarter, you can get enough squares to make two stars. A cutting guide and fabric requirements for additional sizes are included in the free project sheet.
UPDATE: I've added a bonus cutting guide for using Layer Cakes and Charm Packs.