Note: This is just a continuation of my previous post.
Refrain from letting them 'learn a lesson the hard way' - We usually think that failure is what will make kids tough and confient about the things they can do to make their conditions better. According to child psychologists, this is not always the case. When kids fail and fathers (particularly) let them go through the failure without any form of guidance, kids feel and think of a couple of negative things: a) they themselves are bound to fail in any situation or task b) their parents do not care at all if ever things go wrong with them.
Doing everything for them to ensure that failure will be kept by the threshold is a different story though. Let us say your son has a term paper to turn in with in two days. To ensure that he'll pass the subject, you managed to work on three-fourths of the paper so he he'll just have a few things to work on. This example makes an irresponsible som who is proud to know that his dad will answer for anything wrong deed he does. To keep him from failure but not make him dependent on you, help him every step of the way. Let him do the planning and the management and just assume secondary roles.
Tell them pointblank that you believe in them - This needs no further explanation. Just do it and its magic will work.