Here is the advice: - Avoid vertical lines - Avoid “boxing up” cells, usually 3 horizontal lines are enough: above, below, and after heading (see examples in

Here is the advice: - Avoid vertical lines - Avoid “boxing up” cells, usually 3 horizontal lines are enough: above, below, and after heading (see examples in this guide) - Avoid double horizontal lines - Enough space between rows - If in doubt, align left I agree with this, although some of his examples I would tweak slightly, and sometimes I wonder about how much better "align left" ends up working.