Artificial Neural Network

Did you not partition your data (before starting training) into training data and test data? Do you have any Idea about the theory behind neural networks? The way you have asked the question, I doubt it.

You haven't given us any specifics about your neural network. "How to train a neural network?" is a basic question the forefathers of neural networks had. It's a general question and therefore I'm gonna have to give you a generalized (and probably lame) answer.

Suppose your neural network is intended to categorize pictures into two classes: Facial pictures/Non-facial pictures. You first find out a bunch of pictures from both classes.

Then you build the network, and use some of the pictures (normally about 80% of data) to train it. In training what you actually do is, input pictures, and tweak the network until you get the correct output.

After training the network, you input the rest of the pictures into it, and see what output it produces. If the network could categorize the rest of those pictures correctly, you have built and trained the network well.

Then you write a paper and publish it, and you're famous.