Professional web design firms run their sites through a vigorous quality assurance phase before going "live." They generally keep a bank of computers of varying platforms and processing powers that run as many versions of browsers (including Lynx) as possible.

If you do not have the resources to keep a similar setup on your own, make the site available on a private test site and take a look at it on your friends' computers. You might view it under corporate conditions (a fast Windows machine with a 6.0 browser and a T1 connection), then visit a friend at home to see the same site on AOL with a 28.8 modem. (If nothing else, this is a good excuse to get away from your computer and visit your friends!)