Make sure the hitch coupler's locking lever is in the down position, the ball is locked to the coupler, and a pin or padlock is through the locking lever. If the trailer is equipped with brakes, check their adjustment according to the owner's manual, and inspect the breakaway lanyard's connection. Make a visual inspection of the grease in the clear plastic hub and add the correct lubricant if needed. A safety chain should be connected between the boat's bow towing eye and the trailer tongue to keep the boat from jumping over the winch stand in a panic stop. Also, secure a strap between hull and trailer near the boat's stern to keep the boat and trailer together in case of an accident.
Some motors use a separate motor brace for towing.
Secure tackle, coolers, boat covers, and other gear on board the boat so they won't blow out or bounce out, and attach lines to the bow and stern cleats for launching and docking. Replace burned-out bulbs and make sure trailer plug contacts are free from corrosion. Also, check U-bolts bearings and wheel hubs. Make sure the license plate is still in place. Not enough weight on the tongue can cause the boat to fishtail at highway speeds and cause an accident.