How do I make sure clients actually pay my invoices on time?

Set expectations before you start: put payment terms in writing, ideally net-15 rather than the traditional net-30, and require a deposit for larger projects. Invoice promptly the moment work is delivered, since delays signal that late payment is fine. Make paying easy by accepting cards or ACH directly on the invoice. Number every invoice, state a clear due date, and add a late fee clause you're willing to enforce. Automated reminders a few days before and after the due date recover most stragglers without an awkward call. For repeat late payers, switch to upfront or milestone billing. Persistent nonpayment may justify pausing work, sending a formal demand, or small-claims court. Cash flow, not profit on paper, keeps a solo business alive.