I highly reccommend you check out Peep Laja’s blog, ConversionXL. Even for the non website designer, it is a wealth of extremely useful information about how to make your website sell. Peep cuts right to the chase.
“Larger font is easier to read than small font. The font size should be at least 14px, or even 16px.
Line height is the distance between two adjacent lines of text. If there’s more space between the lines, it’s easier to read. The optimal line height is 24px.”
From ConversionXL’s Blog Article – “9 Steps to Improve Website Readability”