ok so one easy way to create an introduction is to re-word the question, you can follow that by a VERY BREIF overveiw of what the essay will contain.
eg, Yolen utilises a range of language techniques in her novel BRIAR ROSE to shape meening for the responder, some include...........................
its important for the essay to be set out logically, don't point out a technique or somthing that is at the end of a book then follow it up with another from the begining, keep it as sequencial as possible, this tells the marker you know your shit, you've got it under control.
the easiest way to to create a logicaly structured essay is by making a plan... even if you jot down 6 words that remind you of each relevant point, number them so you know which order you want them in, then keep refering to it as you go.
above all make sure you stik to the question, each parragraph should contain a new point, at the end of that parragraph write a quick sentence linking your statement to the quote or question they have set out
never EVER introduce any new material in the conclusion - keep it short and sweet, using again a very breif summery focusing on the question or quote which the essay is about.
good luck