Superstition is attributing powers to created things which they do not have.
So, for example, being able to print out *x *amount of copies of prayer y, and attributing to this action a particular result, such as infallibly answered prayer, is superstition. Thinking that one must pray a certain amount of times, or else God will by no means hear them, is superstition. Believing that wearing a Rosary means you never have to worry about avoiding sin is superstition. So on and so forth.
Answering prayer is proper to God alone; something created does not have this power of its own accord.
Now, what is the point of a Novena?
A basic principle of spiritual theology: we only receive the graces we are disposed to receive.
Novenas dispose us to receive the graces for which we ask.
When God sees that we are disposed to certain graces, He will often reward this disposition by granting the grace. But the prayer in no way causes God to do so, He does this of His own mercy. This is why it’s called a grace, and not a payment: it is a free gift because God is a loving Father who wants us to be perfect.
But, of course, God is under no obligation to grant graces, and often enough, our motivations are impure, or we ask for stupid things, or we have natural ends in sight, or we ask for things to fulfill our appetites.
Prayers like Novenas help us, then, to be disposed to graces. They can help us, especially the older ones, to ask God for things that we truly need, and to ask Him in a way which doesn’t offend Him, but which has the proper balance of the fact that we are a creature, that He is God, and that He loves us infinitely, but yet is infinitely above us. Such reverence is essential to approaching God, because reverence leads to humility, and God resisteth the proud, but to the humble He giveth grace.