This involves taking the ideas of other people and putting them into your words and then referencing them. Remember, when you do paraphrase, it is not necessary to use quotation marks but you must cite the source in your text, for example:
Tastes in food are shaped in the same way as tastes in music, that is by influences operating within society (Mennell 1996, p.17)
One of the main difficulties of paraphrasing is that students often express other people's ideas without changing enough of the words. Therefore, the student's words in their assessment look very similar to those that they have read in the original. When your tutor reads your words against the original s/he may decide that they are too similar and this will be regarded as plagiarism, even if you have provided a reference!
Try to read articles, chapters and make your own notes and then write your assessment without the article or book in front of you. Your tutor needs to see that you could have written your assessment without the book next to you!
The Effective Learning Service provides a guide to note taking and other helpful resources on their web page.