After selecting your label type, use the New Document button which creates a
sheet of blank labels. If you cannot see the label boundaries, enable the
Table | Gridlines setting. Now save this as a template and close it. Create
a new document from the template and fill in whichever cells you want to use
that are unused on your sheet of labels.
But please heed Graham's warning: don't do this with LaserJets because more
than one run through the printer may result in a label coming off in the
printer causing far more cost than the few pennies saved using the remainder
of the label sheet.
One of the advantages of creating your own template for your commonly used
labels is that you can format them to use fonts, spacing and margins that
you want.
One of the disadvantages is that with many inkjet printers you will get a
prompted about margins being outside the printable area: you can simply
ignore this though.