By keeping a few things in mind, braking with a trailer doesn't have to be traumatic at all. After you've had a little practice on some quiet streets getting accustomed to braking with the trailer, you're ready for the big day.
You'll definitely want to pack carefully so no surprises pop up along the way. For example, if you have too much weight on the hitch or a load with a high center of gravity, slamming on the brakes can send the front end of your trailer into dive, taking your tow vehicle's rear axle down with it. Unless you're looking to go somewhere over the rainbow, this is a bad thing. So definitely take the time to make certain everything's stowed carefully. You can get more tips on how to do this by reading How to Load and Unload Towed Vehicles.
You're finally underway, but nobody else on the road seems to understand how eager you are to get to the lake! It's a pity, but it's just something you'll have to accept. Some of the worst things you can do while driving a trailer are drive too fast or follow too closely, let alone ride someone's bumper. Stopping with a trailer takes roughly double the time it takes to stop a solo vehicle, and it can take even longer depending on the weight of the load. Plus, with more speed you get more sway (swing from side to side). If you do experience sway, taking your foot off the gas and gently applying the trailer brakes can help ease this movement; slamming on the brakes of the tow vehicle can be a disaster. Always keep your driving slow and controlled, with ample distance between you and anyone you're driving behind.
If lesson one was all about space and speed, lesson two focuses on anticipation. Keep an eye out for anything that might mean you need to brake ahead. Did somebody just pull out of a parking lot in front of you? Are people merging onto the highway? Is there a traffic jam up ahead? You always want to have a heads-up for a potential need to brake.
Another thing you want to keep in mind is the use of engine braking, also commonly called compression braking. Engine braking (using lower gears to slow a vehicle instead of the brakes) not only helps your brakes last longer, it also spares them from overheating, something that happens much more quickly when you add the weight of a trailer to a vehicle. If you're doing a lot of braking, say in order to go down a hill, you'll probably want to practice engine braking along the way. You can use it at other points in your drive as well. Your brakes will last longer and you'll know they'll be there when you need them. But over time, it will increase the wear and tear on other parts of your vehicle, as well as cost you more in fuel.
One other thing to note in relation to the brakes -- you don't ever want to keep your foot resting on the brake pedal when you aren't trying to slow down. The smallest pressure will cause the brakes to operate at a low level and wear them out that much faster.
So basically, the trick to safe braking when you're towing is to get a feel for it ahead of time, use a redundant brake system in case something unexpected goes wrong, pack your cargo carefully, don't speed, leave yourself plenty of space to brake while anticipating the need to brake ahead of time, and last but not least, take it easy on your brakes -- they'll make or break your trip!
For lots more links about towing, braking and the laws of motion, stop on the links on the next page.