"When the woman saw that the fruit of the tree was good for food and pleasing to the eye, and also desirable for gaining wisdom, she took some and ate it. She also gave some to her husband, who was with her, and he ate it." NIV translation
We often think of Eve going behind Adam's back and eating the fruit and tricking him into eating some. Here, we see that Adam was with her when she ate and wonder why he did not even try to stop her. This origination of sin has often been laid at the feet of Eve, but, Adam could have stopped her.
"Then the eyes of both of them were opened, and they realized they were naked; so they sewed fig leaves together and made coverings for themselves." NIV translation
Their eyes were opened and they knew they were naked. Instead of stopping to see how ridiculous this was, they chose to make coverings for themselves out of fig leaves.
Throughout the Bible, we will see that figs and fig trees are a symbol of safety and security.
"Then the man and his wife heard the sound of the Lord God as he was walking in the garden in the cool of the day, and they hid from the Lord God among the trees of the garden." NIV translation
Then, they heard God and decided to hide from Him. You see, they knew that they did not belong in the presence of God anymore as they knew they were guilty of doing evil.
"But the Lord God called to the man, 'Where are you?'" NIV translation
God knows everything, so, why would He ask this question of Adam? It was so that Adam could realize what he was doing. He had gone from walking in the garden with the Creator of the universe to crouching behind a bush in a very short time.
"He answered, 'I heard you in the garden, and I was afraid because I was naked; so I hid.'" NIV translation
The fruit that they had eaten opened their eyes to sin and so, with that knowledge came fear. They realized that they no longer belonged in the presence of God and so they tried to hide. The same thing happens to many people today as they try to hide from God because they do not understand His mercy and grace. Because of the fact that Jesus paid our penalty for sin with His very blood, we belong in the presence of God once again.