If you have a very short--and important--web page, you might want to raise the basefont of the entire page.

A value of three is the default and will display the body text at the size specified in the Preferences or Styles dialog box. You may choose any value from 1 to 7.

You can use the <FONT SIZE="n"> marker to change the font size relative to the base font size.

You should remember, however, that you are messing with your user's preferences. If she chose to display her body text at 12 points, it may annoy her to no end to have you decide to show it to her at twice that size.