Approach the drop into the ravine very slowly using your slow ride skills to maintain balance, keep the bike straight, and to stay in the standing position with both feet on the footpegs. The slower you can ride over the lip the slower and more in control you will be at the bottom.
Once you "drop in", due to the steep angle, gravity will take over and you'll speed up significantly despite using the brakes aggressively. Be sure to extend your body way over the rear of the bike to help keep it on the ground, and don't let either wheel be continually locked up.
As you are getting to the bottom start increasing the revs by rolling your wrist, using the "Door knob" technique to make this easier, then accelerate aggressively through the bottom. Transition your body to the center of the bike, brace your arms and don't buckle at the knees (due to the excessive "G" forces present) otherwise you'll lose heaps of momentum and control from the bike becoming very unstable.
Accelerate hard up the other side moving your body weight as far forward as possible which helps keep the front wheel down and you on the gas. Achieve this by not bending your legs and extending your upper body fully forward, aiming to have your head out towards the end of the front fender. Make sure you look to the top - where you look is where you go. Your goal is to have to apply the brakes at the top to slow down instead of being 2/3's of the way up and needing to speed up.
Minimizing speed down into the ravine and maximizing acceleration through the bottom and on the initial climb out, plus using full extension of your body from the back to the front will give you the best chance of conquering such advanced trail situations.