That way one should offer prayers, love and gratitude to divinity every single day. But special days have certain importance. Whatever knowledge I have recieved from my Guruji Naushir gives this festival a deeper meaning.
Shivratri is celebrated in remembrance of Lord Shiva. It is this day when Shiva ji saved the world from the harmful effects of the poison called HALAHAL that emerged as a result of Samudra Manthan. Keeping the story part aside Guruji Naushir explained that , Shiv ji is one of the entities that are constantly absorbing negative energies and maintaining balance on Earth. The Humanity is constantly throwing huge amount of negative energy in the form of negative emotions, thoughts, words and deeds, this huge force of negativity can harm the world. paying gratitude and reducing the negativity within will be real worship and tribute to this divine form.
When a spiritual seeker worships shiva by chanting Om Namah Shivay, Shiva Ji absorbs his negativity too, and helps the soul to progress faster. The SHIVA is actually the Destroyer of negativity and hence worshiped by even Gods and referred as MAHADEV.
One can observe fast and chant Om Namah Shivay on this day, and keep the mental process pure.