Doing the bunny hop is very difficult and most ppl dont know how to do it,
i also had very much difficulty in doing the bunny hop,
but as they say practice makes perfect , you can also do the bunny hop :
1. move forward by pressing w
2. now release w key and strafe(a or d) and move mouse in the direction of strafe+jump
3. this will cause a forward angle jump.
4. now u must not use the w key to move forward
5. When your just about to land after the first jump, hit the opposite strafe key and curve your mouse in the same direction of your strafe and hit jump EXACTLY when you land after the first jump. Doing this a little too early or little too late will cut the bunny hop.
6.IF You got the timing and mouse movement right you will quickly move forward faster, and you will need to repeat Steps 2 to 4repeatedly.