I like the way Alan Weiss has on his book The Consulting Bible. It basically says that half the fee is due on acceptance, with the balance due in x days. Altern

I like the way Alan Weiss has on his book The Consulting Bible. It basically says that half the fee is due on acceptance, with the balance due in x days. Alternatively, offer a 10 percent professional discount when the full fee is paid on acceptance. Make it non-cancelable and that the agreed-upon payment terms are due as described. Let the client postpone or delay any part of the work as they think it's necessary. Guarantee the quality of your work and offer them a full-refund if it doesn't.