If you did the winterization correctly there should be little to do besides put in the battery. Moisture contamination is probably the biggest concern after long storage. If you put Sta-Bil or some other type of fuel stabilizer in a full tank of gas over the winter that should not be a concern for the fuel. I recommend pulling the spark plugs and checking them. Some recommend changing spark plugs as part of getting ready for the new season. If your engine was fogged properly in the winter you should be OK. Check to be sure throttle, reverse, trim, etc. cables move freely. Again they should have been lubricated as part of the winterization process, but if not done properly they could be corroded or rusty and sticky. If you changed the oil as part of the winterization process, don't forget to check the oil levels (4-strokes) during the first ride after the engine is warm, and bring along some extra oil just in case you need to add a little. Don't forget to check out the trailer. Tires will need air, check electrical connections, hitch connections etc..