Bjorn Brembs (@Brembs) writes:
1) Don't insult or threaten your customers. If, for instance, they complain about your mistakes, apologize and promise to not make that mistake again.
2) Don't charge your customers so much that you make profits which would make Steve Jobs rotate in his grave in envy. Like people looking into Apple's business practices in China, people will start checking where these profits come from, if they're seen as too excessive. That's the case for any business, but especially so if the money you're charging comes from tax-payers who weren't asked if they want to line your shareholders' pockets with their hard-earned cash.
3) Finally and perhaps most importantly: Make sure you have a good case for charging the money you charge. If you try to prevent publication of the part of the work you didn't add your value to (i.e., the preprints of the scientists who submitted their work to you), you send the unmistakable message that you find your contribution to scholarly communication to be so worthless, that nobody would pay anything for it and that you expect people to rather would read the work without your added value, then pay for your added value. In other words, believe in the product you're selling, or don't try to sell it.
Heeding these three simple rules won't guarantee you stay in business, but violating them will almost certainly guarantee you'll be out of business soon - with about the same certainty with which one could predict that anybody would turn and run from a charging lion.