To begin with, I would suggest that you make your essay more specific. If you are going to write an essay based on a poet, the place to start would be to identify one or two of the main themes or concepts that are brought out in their work and then to use that as a basis of your essay. This will give your essay more focus and allow you to keep on task.
One of the central aspects of Heaney's writing is the way that he writes out of his Irish context. Heaney is famous for the way in which he writes poems that capture life in Ireland through rhythms and verbal melodies as he focuses on nature and his experience of Ireland as a whole. What makes Heaney so special as a poet is the way that he is based so strongly and physically in his native Ireland but manages to write poetry that is based on universal themes and manages to connet with everybody. This is his one of his central defining characteristics, as when we read poems such as "Half Term Break," which captures his own autobiographical experience of losing a brother, even though it is in a very distinctive Irish context, he explores the subject of grief that touches us all. He therefore produces a link between a very specific and individual context and the life of the reader, no matter where they are from.
This would be an excellent aspect for you to explore as you write an essay on this poet. For other suggestions of poems that you could use to write on, you might like to read "Digging," "Follower," "The Forge" and the sequence of sonnets he wrote after his mother's death. They are very accessible and would provide you with a good entrance point to his work.