Or if you want to print just a grid (graph paper, for example), and you're
not planning to draw or type anything on top of it, set margins to 0"
(ignore Word's screams), create a table of w x 2 columns (where w is the
width of the page in inches) and h x 2 rows (where h is the height of the
page in inches). Set the row height and column width to 0.5" and apply a
grid border. You won't be able to print the grid all the way to the edge no
matter what method you use, but this might be quicker than Jay's drawing
lines (took me just a few seconds).

For a slightly saner approach, let Word have a half-inch margin all around
and eliminate two rows and two columns (I had one row spill over to the next
page--no issue with columns).

--
Suzanne S. Barnhill
Microsoft MVP (Word)