Here are some tips for problems that I see happen a lot at boat ramps. Your boat will launch, and load onto the trailer much easier if the trailer is not "high" in the front. I see some guys pulling boats hitched to the bumper of a high-riding vehicle (4-wd usually). This makes it very hard to get the bow of the boat to go up & over the roller of the trailer when loading. It's definitely always best if you get a receiver type hitch, and the proper drop insert for your rig. One of those drop hitches you bolt onto the bumper might work too (But, a good receiver hitch that's rated for your rig's weight & bolted to your frame is the best way to go). This distributes the tongue weight a little farther forward on your tow vehicle. The other thing I see quite often, is people backing the trailer too far into the water (especially when loading). Most boat's trailers are easiest to get on when the running boards not completely submerged in the front. If a ramp is very steep, this is even more important. The boat should come into contact with the running boards (or bunks) well before the bow reaches the roller, or stop (right at the winch). The running boards will then raise the bow of the boat, and allow it to meet the roller, or stop pad at a much better angle. If you look, you will notice lots of boats around with damage on the bow (nose of the boat), and that is usually caused by running into the roller, or even under it (Bad Load angle). The next thing to watch is to make sure you are not going to hit the bottom with your prop/skeg when loading. Normally when you are making your approach, and the boat makes contact with the runners, that boat will stop short of the front roller. At this point trim the motor up enough that you are sure it will not hit the bottom. Then give it enough gas to push up tight on roller, or stop pad. Please trim the motor on up, before pulling up the ramp. (I have seen several people ruin the skeg on the foot of there motor by forgetting to do this). Practice is the key, and don't get rushed & forget to do something because there is another guy waiting on the ramp. There is nothing that will ruin a good fishing trip worse than causing some expensive damage to your rig while loading it up to go home.
Hope this helps somebody...Good luck, and please practice catch & release.