Hei Caitlin! :D
First of all, you do a great job by planning your essay before writing it! That's the right way to do it.
What should I be looking for in this close study essay?
If you have to write about a book without having been given a concrete prompt, perhaps it would be good to think about a particular incident in it, or a thought or a character that impressed you and build your essay up on that.
In such a case you need to summarise the essay first of all. While summarsing make sure to comment on what's happening. If you plan to add something afterwards, that is not so no good, because it would be pretty much ripped out of context. (Here you will also incorporate your key incidents.)
You should mention themes that seemed to stand for what you're analysing. I haven't read this book, but I'll give you a random example. Let's say you have a novel about war and love, but you want to look closer at the loving part; or, in your opinion, the accent falls on the loving part. In this case you do mention that there is a war going on, but you care more about love. [sorry, for repeating so many words]
I don't really know how relevant form, structure or language features might be to. If you think they are of great importance, perhaps you should mention them, but I never really talk about them so I wouldn't know where to tell you to incorporate them. [I do remember when I was writing essays on plays and such that I would mention language features when talking about a character. Form and structure ... hm, look around and see where they best fit in.]
It is obvious that a charaterisation will fit in perfectly after mentioning the themes. Always remember to create a comparison based upon the interactions between figures.
And then write a great personal opinion down and finish the essay off with a thoughtful conclusion.
Here's all I've been saying as a scheme:
1. Introduction (Give the reader a hint on what you are going to develop in the upcoming essay. You could also choose a quote to begin or talk about the author and such if the events in his life are relevant to what his piece of writing is about.)
2. Body
summarise the given text and comment on what's happening at the same time (key incidents go in here too, even though you are free to talk about them in more detail after)
- mention themes and try to underline the most important one(s) to making your point
- talk about a character
- enclose a personal opinion on the matter you chose
3. Conclusion (Basically, you present the main idea of the intro again and add some more info to it.)
Good luck with this! :D