J Hop on a Mountain Bike

This guide will tell you how to easily bunny hop with a mountain bike within approximately 1-2 weeks with practice.

Steps

Start riding on your bike at a comfortable pace, maybe {{safesubst:#invoke:convert|convert}}. Keep yourself in the center of the bike at first.
Bend down and lean over your back wheel a little bit.
Once you have your lower body over top of your back wheel and lift up and push down at the same time a little bit forwards with explosive action.but make sure you have your front wheel up before you try to push down and forwards
This is the part where everyone messes up. You are not going to just lift up and hope the rear comes up; there is a trick to it. The point is that you have to leave the rear of the bike weightless and after you have your wheel still lifting up over the ground you then have to throw your body forwards and push down on the handle bars.
Level off to clear the object better, or just to get more air. While in the air, push forward and kinda "rev" the handlebars although twisting the handlebars is not always necessary, making the rear wheel level with the front.
Make your landing. Try landing on the rear tire or on both. Landing the front tire first might mess you up and go over your handlebars, unless you have awesome control. If you're j-hopping high or off an object, try absorbing the landing with your body by crouching at the bottom of the land, like a chain reaction from the bottom to the top(updated 2013).

You might not notice that you're actually getting air until your friend tells you. Therefore, you should practice with your friend.
This maneuver is most easily done on a street/urban or trials bike, but can be done on all!!! If you don't have a street/urban or trials bike, I encourage you to keep trying on it anyway. If you do ever get one such bike later on, it will be much easier if you've already learned on a cross country or downhill bike.
Remember to push back and 'up' with your feet, 'curling' your toes / feet around the pedals. This is essential!!! With practice you can get air up to several feet over a few years of perfecting (the first foot comes in a couple months so try hard!)
Best results come from a front first lift followed by an explosive serge of the pedals.
Never give up after the first few tries. It can take a month to actually get it up to {{safesubst:#invoke:convert|convert}}, so keep trying, please.

Always wear a helmet; yeah, you might think that it's not a hard trick and that you won't get hurt but you never know...
Try doing it with a friend, we don't want a body on the street screaming for help, do we... (Note: If you do not have any friends, get a classmate or Co-worker.)