Do you mean ROTE learn?
because it varies with different people. I can't abide learning by rote, it's the slowest way to learn. I'd rather not memorise an essay and just use points in an exam...that way you can compose a fresh response to the question being asked. if you try to memorise specific english essays answering one type of question, you run the risk of being totally screwed if you get a question that is so far removed from what you've memorised that you can't adapt it to the question.
when I'm forced to memorise, I surround myself with the text. I read it onto a tape and then listen, stick quotes up on the other side of the shower screen, practise typying out paragraphs. All are pretty time-consuming, but it also depends on your own innate ability to remember.
also, summarising into points and drawing mind maps won't help you remember word for word, but they'll give you a good idea of how what you're learning fits together. This works particularly well with subjects like chemistry, physics, business studies and the distinction courses. t's also good to draw a skeleton structure every essay response you memorise (if you choose to do this) for English, and have extra points you can use to expand on what you've written if you're required to.