Making figures for publication
Generally, the best idea is to size your figures so that they can fit in a column of text without needing resizing. Another good rule of thumb is to choose font sizes to be the same (or close) to that of the main text. This troper has found that using the postscript terminal is usually best. Depending on how picky you are, you can just use a common font or try to match fonts with LaTeX (details are here). This troper finds the following usually works well:
set term postscript enhanced color size 3.4039,2.1037 font "Roman" 9
The size here is to fit nicely into an APS 2 column format. I'm not sure why yet, but the postscript font size does not appear to match up with the LaTeX font size, but size 9 seems reasonably close to revtex4's default size 10.