Here's an idea; get an old RIGID mountain bike, and pump up the tires - hard. Run 10 PSI above the tire's limit, and ride everywhere on that bike. Go off curbs and bunnyhop and all that, and it'll force you to be smooth. Ride it to school, to work, to the park, to your friend's house . . everywhere. Then you'll learn to be smooth.
Well, if this is downhill related, learn to pick your lines. You should constantly be checking the terrain ahead of you to find the easiest route through technical sections, don't just go slamming into rocks and plowing over them. Also land drops smoothly, with both wheels at the same time, that will help take the stress off of the components.
When you are training: Set your fork and shock harder than you would normally. This will teach you to use you body to float over the terrain and ride smooth.
get a hard tail and rid that on dh runs every other time you ride, it is one of the best ways to learn.
take your chain off your bike and ride it, this forces you to carry speed and pump the bike more to be anyway fast. in order to carry speed youl have to be smooth, so this should help you to become a smoother rider