I've been working on an on-point quilt, which requires corner and setting triangles. The blocks are big, so I could only get two squares per width of fabric. My instructions say to cut x many squares. Cut 2 squares once diagonally for the corner triangles, and cut the remaining squares twice diagonally for the setting triangles.
There is quite a bit of WOF left from the squares.
First, I cut a WOF the size of the squares I needed, the red line. (Please cut straighter than my wiggly lines!) I cut the first two squares, the blue line, and had a big chunk left over. The fabric is folded as it comes from the bolt, the fold on the right, the squares cut at the selvedge on the left.
The second diagram shows refolding the fabric to just wide enough to cut the squares, leaving a continuous length of fabric all in one piece.
The darker green represents the right side of the fabric, the lighter is the wrong side of the fabric.
Since I need an odd number of squares, there is a lot of WOF left from the last square. This last diagram shows cutting the last triangles from a single layer of fabric. 
I chalked the outline of the size of the square, and the diagonal in both directions. The first cut is the red line, cutting diagonally from corner to corner as you normally would. The second cut is the blue line, cutting only the triangle made with the first cut (red line), cut on the chalked line. The white is simply what I had outlined with my chalk marker, and is uncut.
The fabric is a secret yet, so I can't show the whole square/triangle/fabric. The space going from bottom to top is the red line cut, the space to the left is the blue line cut.
The border is cut of this fabric also. For the border, instead of cutting WOF strips and piecing end to end to get the length needed for the border pieces, I cut from the length of fabric. With the fabric I have for this particular project, what I have left from the refolded squares is more than I need for the side borders. Since I didn't think of it before cutting the first WOF, there isn't enough width left for all four borders, I will have to piece the bottom border.
Even if you have different fabric for the border, you could still cut the triangles this way, and have one continuous piece left to put into your stash.
Maybe you'll find this helpful and one day use it for one of your quilts!
