The introduction doesn’t have to be too impressive, just a few lines. Rephrase the question, name both of the book title and authors. Give a very brief summary of each plot if you like. If you can, insert an interesting quote here. You might like to write how you are going to compare the books, too.
The conclusion however, must be top notch. You need to come to a conclusion (this may be obvious, but some people are very vague. Be forthright!). You should sum up and revisit your better points. It’s good to put your own opinion in, say which book you preferred the way whatever it is being portrayed in. Definitely get some quotes in here, don’t analyse them of course, just weave them in. I think if you can finish with a really good quote, that’s very impressive. For example, if you were comparing it, you could finish with “and it really was ‘much ado about nothing'”. Bang.