Using a frame story for the introduction and conclusion should be familiar to you from lots of movies.One good example of a story frame is UP. In this case, the movie opens with the frame of Carl looking at the scrapbook Ellie has made for him about their life and dreams, before flashing to the present story of Carl and Russell and their adventures. The movie returns to the frame at the end of the movie as Carl looks at the last page of the photobook Ellie has made for him. He learns that it was the journey of the relationship which was the real adventure.
Another kind of frame can be a flashback. In this technique, you start in the middle of the action (or after it is over) and then flashback to an earlier memory. The Notebook uses the story of a man spending time with his wife with Alzheimer's as the frame for his re-telling the story of their romance.
The advantage of using a frame is that it makes it easier for you to talk about the meaning of the story, especially if you use the present day to flashback to the past. Be sure the frame is not just random. There should be an event, object, conversation, or situation which causes you to flash back in memory.
Is Tess in ‘Tess of the d'Urbervilles' portrayed as being responsible for her own demise? [pdf 40 KB]
Yours is a beautifully clear essay. You write very well, and your prose is delightful to read. You've also done your research and it shows. There is a remarkable lack of vagary about society or feminism in your piece, and you've picked canny quotes from your secondary sources that elucidate and situate your arguments.
You've also located some wonderfully specific quotations from your primary source to support your argument that Hardy's narrator sympathises with Tess. Some of your close readings are wonderfully astute, as when you point out that Tess implores Angel, rather than commanding him. Slightly less persuasive is your assertion that Tess is the victim of Alec's eyes; I suspect you might have found better quotations, descriptions, or incidents denouncing Alec's gaze.
You are clearly very good at pursuing and proving an argument. I encourage you to be a bit more experimental in your next essay; perhaps choose a less straightforward topic and see where it takes you.
Please see penciled notes throughout on shortening sentences and watching for comma splices (please look this term up in a style manual if it is unfamiliar).