Make notes under separate headings - adding your own views about how theories can be complementary - or opposite approaches.
Follow up further sources and make use of journals, research papers, encyclopaedias, dictionaries, etc.
Record all the sources at the time you use them, including page numbers, ready for your List of References. (Researchers and postgraduates may find a PC bibliography package, such as Papyrus, useful.)
Brainstorm. Having examined the title thoroughly, write down all the thoughts and ideas that come into your mind at this stage. Decide what information you need.
Start researching early to take advantage of relevant and useful ideas that come up in lectures, seminars, discussions or general reading.
Start focussed reading. On some courses you will be given booklists which will provide the main source of ideas and information - otherwise access the Library catalogue for relevant material.
Read selectively and purposefully. (You don't have to read books from cover to cover.) As you read, begin to formulate questions. How will this be relevant to the essay? Will this support my argument - or cause me to change my views?
Each paragraph should link naturally with preceding and following paragraphs.
Leave the first draft for a day so that when you return you will look at it more objectively. Make sure that your plan is coherent. Change paragraph order where necessary. Add what is missing and delete the irrelevant.
Edit the paragraphs , checking for ambiguity. Change wording; correct grammar and spelling.
Make sure that you have acknowledged all sources in the Bibliography/List of References.
Write a first draft just as the ideas come. Don't worry about precise wording.
You don't have to start writing at the beginning. Begin with the section that you feel will be the easiest.
Write in as clear a style as possible so that your reader can understand you. Avoid abbreviations and slang.
Write in paragraphs . The first sentence will introduce the topic or theme - as a sign-post of what is to follow. Then develop the idea or argument and back it up with the evidence. The final sentence in a paragraph may summarise the point and/or refer back to the essay title - unless the following paragraph is continuing on to develop the same ideas.