Ten-minute quick win: make one short list of invoices that are past their due date.
For each one, write only three things: the client, the amount, and the date you'll follow up. Then send one friendly nudge today. You do not need a perfect collections system before you start getting paid on time.
Small, consistent follow-up protects your cash without turning you into a different kind of business owner. Comment "list made" when yours exists.