When I do my flying geese, I draw a line from one cornor to the other on the small square. This really helps in sewing a straight line. I have a nice machine with all the ruler lines on it and drawing the line is still the best way for me to go. Also, I have a small piece of cardboard and wrapped it in 220 gauge sandpaper. I put my pieces to be drawn on this and it grips the fabric just enough and you have a nice straight line.
Here's a link that will give you different options in making them:
http://www.quilterscache.com/H/Howtomakegeese.html
Good Luck!!