Not planning for delays
Airlines are leaving less time between arriving and departing flights, so book morning departures to avoid cascading delays. Also be aware of seasonal weather patterns like stronger headwinds on international and transcontinental flights that can delay the return trip. If thunderstorms or snow are possibilities, pick a different connecting airport.
When a flight is delayed or cancelled, indicating you'll miss a connection, get rebooked immediately before taking off. Planes are often full and have few seats available for standby customers, which are prioritized by the time of their request. In a worst-case scenario, take care of your own expenses and request reimbursement rather than wait in an hours-long line for overnight accommodation.