Several of you have made the block for week 1 and it ended up measuring less than 12.5". If that happened to you, here are a few things to try.
First, sew a seam and measure it with a ruler. (double click on the image to see it larger.) It should measure exactly 1/4". If the seam is larger, your block will end up too small. Also, you will end up losing the points of your triangles. It does take some practice. When there are so many seams in one block, accuracy really becomes important. (Don't think that I have this perfected, I still have missing points in a few of my stars.)
If your seams are accurate, the next thing to check is your cutting accuracy.
There is an alternative to this. If you really don't want to worry about the accuracy, you can add white borders around your blocks to make them a uniform size and choose to set the block differently than in this particular star quilt. (Something along the lines of this quilt, do you see how the blocks float in the white?) That is one way around it. But I would encourage you to keep trying for the accurately sized block. It does get better with practice.
OK, so on to block 2...
cut one square 6 1/2" from a medium print fabric
cut one square 7 1/4" from the background fabric
cut it on the diagonal (twice) to make 4 quarter square triangles
cut 4 squares 3 1/2" from the background fabric
cut 4 squares 3 7/8" from a darker printed fabric (the contrast is important for the design of the star to stand out)
cut each of those squares in half on the diagonal to make 8 half square triangles
layout as shown
Sew together and square it up so it measures 12.5".
Once you are done, you can add your photos to the flickr group here.
If you have questions, I will attempt to answer them in the comments.