It means he is going to take an active role in your life, to ensure you understand the Faith, and help keep you on track. He will be there (theoretically) whenever you need help or a shoulder to lean on.
You shouldn't expect yourself to be "perfect" to the point that you wallow in self loathing and guilt, and get bogged down in misery. However, you should set a goal of perfection for yourself....and try your best to achieve it....knowing full well, that you will stumble and fall....just remind yourself to get back up and continue the journey.
We can't allow ourselves to think we are "good enough" lest we get in a habit of sin and think nothing of it. We need to recognize our sins, confess them, and make an honest effort of not repeating them.
I'm a godmother and I take the role very seriously. I believe that one day I will be standing before God and not only answering for my own actions, but, to a degree...answering for the actions of my godchildren....and what I did to help them, teach them, etc.