How to minimize getting stiffed from patients

All good advice.

Credit cards are a good alternative, as well as an object lesson to everyone that waiting for money costs money.

People who ask to have bills sent to them should be treated just like clients of other businesses: credit is earned. New patients should expect to pay at the time of service. You need to insist on payment. Everyone should be given a bill at the time of service unless the insurance coverage is guaranteed. In any event, Co-payments, deductibles, and fees for non-covered services need to be collected on the spot.
Front desk personnel need to be assigned the responsibility of cashiers, and held similarly accountable. If you aren’t fully paperless with account entry at point of service, then triple verification and receipts for all payments need to be in place, with receipts for every encounter, even those where no money is paid. The checkout/check-in needs to be treated with quality retail-level accountability. It sounds harsh, but these are the places small practices bleed the most.