One important thing to overcome before going into marriage

Slothfulness. 

When a child is born, from the time he or she is able to walk, whatever he or she sees an elderly person do, especially his or her parents, the child would always want to do it, or try to imitate, even if the child can't or won't be able to do it, but you'll see the child try to do it. But you'll discover, when the child grows alittle more to the age of being able to do those things, you'll discover slothfulness creep into the child, so much so that, those things you once used to shout at the child to stop doing, you'll now be like forcing the child to do those things for you.

Now this slothfulness would continue into the teenage of the child, such that you'll have to at some point, be enforcing the child to do even that which is of his or her best interest; and so the child continues to grow enjoying the help and decision making of the parents.

Now the child has fully grown, and has reach the time he has to be the one taking decision and executing it all by himself or herself. At this point, the now grown up child would begin to know how hard and tough it is to make decisions and to execute it. So the child has to overcome the realm of slothfulness that he or she was born with, and was accustomed while under the parents. 

So the now grown up child has to overcome the slothfulness before he or she sets into marriage, else it would be very tough in the marital home for him or her to meet up the demands of the home as a family. 

So mental immaturity and lack of willpower is oftentimes the cause of marital problems, hence, it's always expedient for a man or a woman to strife to overcome the slothfulness of youthfulness before beset into marriage.