first of all state your opinion which is 'knowledge can change our life',then you need to explain how it will change your life and why (hints:knowledge keep you away from many troubles and mistakes,it gives you wit and abilities,it helps you in your life and give you a good studying result).
The second paragraph you need to write a story of your own experience,a story (or two stories) that supports your opinion.You can also write a story in contrast that shows ignorance will bring troubles and frustrations.
At last start another paragraph to conclude your opinion.