I would like to second this great advice. A somewhat shorter piece of reading is 'Mathematical typography' by Knuth (published in the Bulletin of the AMS but I

I would like to second this great advice. A somewhat shorter piece of reading is 'Mathematical typography' by Knuth (published in the Bulletin of the AMS but I believe is freely available online). This article outlines the (enormous) scope of the problem (even before multilanguage typography is considered, or any graphics for that matter).