You don't need to pre load on every jump as it depends upon the jump. If you need to make the bike go further (especially if the run up is not all that great) then you pre load to make the bike go further than it would.
Have a look at this site as it explains pre loading. But on some jumps you use different techniques like if you want to shorten the distance the bike goes as you are hitting the jump hard but have a landing that may then go straight into a corner than you need to squash the landing instead as if you preload you will over jump and land in the corner.
Being fast is all about getting from A to B in the shortest time and that does not always mean jumping higher and longer. Jumping higher without the need only slows you down as hanging in the air is slow.
Perhaps also see about doing a school to work on your technique as if you want to get better being a pro is all about being able to read a track with only a short practice time allocated to get it dialled in. It all just comes with time and experience.
http://www.ehow.com/how_2211350_prejump-…
