Sometimes your weight is a little too far forwards. See if you can pedalkick, then backhop, then kick again. Also, as someone mentioned, good gapping practice is setting two planks of wood on the ground and jumping between them, and moving them apart. To go further, you want to lower the front end, and crank the pedals back a bit, then explode into punching the pedal down, throwing your weight forwards and slightly upwards to move the bike. Where I am now, I need to learn to move my own weight more, and take the bike with me. That, I believe, is the secret to huge gaps. You say you've got there after one day? Well done dude, it's taken most of us a lot longer to get there.