I love crosshatch quilting. It looks good on all quilt patterns. For all over cross hatch I use this to have exact lines marked. I start marking in the middle from corner to corner. The straight edge ruler is 2 1/2" wide. It is very inexpensive too. I have the 4ft and 6 ft. one.
http://www.lowes.com/pd_119896-52044...11480006281312
I use a chalk marker to run down the length of the ruler on both sides. Then move the ruler to the right or left and mark to the opposite corner then repeat from the middle to the other corner. I get straight lines evenly spaced every time.