We all seem to have slightly different methods. I normally undertake this singlehanded: bring the boat on its trolley to the trailer and rest the front of the trolley on the axle, remove the jockey wheel, put a folded cover or something soft under the transom, lift the trolley until the transom touches the ground, lift the trailer (10″ wheels) to the same angle as the trolley and wiggle it into position, then lower both together and do a final wiggle to locate the trolley on its locking pin. 😛