Approaching the gap, sprint to increase your speed. Keep your eyes high, looking past the hole.
Get up off the seat, and level your feet on the pedals. (Most of us have a "preferred foot
forward" -- if we usually jump with the right foot in front, it seems clumsy having the left
foot in front. Practice bunny-hopping while alternating your leading foot.) Center your body
over the crank, feeling the weight in your feet.
As the front wheel reaches the edge, jump as if you're going up for a basketball rebound. The
bike will compress down (with the weight going straight through the crank), and both wheels
will rebound up equally. Lift up lightly with both hands and feet, then wait for the bike to
return to earth. Practice longer and longer jumps -- for this jump, "flight distance" must
be 8 feet if the rear tire is to land on rock.
Dip with a tire trap: As the bike drops into the dip, let your body rise off the seat higher than you usually would. Keep your body over the seat -- in "freefall" position.
As the front wheel approaches the bottom of the dip and tire trap, pull the front of the bike up hard under you. (Don't hang back and "wheelie" -- you need to pull the bike up and a bit back.)
As the front tire approaches the far side, your body is actually moving forward of the seat. As the tire touches, put your weight on the handlebars to unload the rear wheel. (Rear tire can lift off the ground.)
As the rear wheel hits the far side, your body continues forward relative to the bike as it climbs the far wall of the dip, with weight on the handlebars.