I think the first mandatory requirement is at least to count the money. Alas! I've seen "investors" who have had luck then many quickly they were sinking because of a lack on self-discipline.
I think that is not necessary to say anymore because that is too basic to know how much you are holding, even a kid knows how much money he has. Secondly, I agree that self discipline is very important because without it even if you have a good money management plan you cannot still implement it.
The best way to manage your money is to know you goal in life, knowing your future plans and your priorities will give you a clear path on managing your money. Further, you cannot achieve your goal if you will not do it diligently.