You need to spend considerable time organizing what you wish to say and how you are going to say it. Even if you have some great ideas and quotations ready in support of your theses, if you do not organize your essay it will appear fragmented.
Once you know what your topic is (it may be what you have chosen or it may have been given to you), you will have to start your research. Your obvious place of choice for research may be the internet. Do not limit yourself to Google but try and use different search engines to gather information. Do not overlook the possibilities of the library as a great source of information. When you do research, it is important not to quote large chunks from one source; rather you should take a few words from many sources. This make you appear well read even if the opposite is true.
Now we come to the central part of planning the essay that is identifying the argument, the claim or the thesis. When you do your research, you will be exposed to the claims and arguments made by the authors you have read and this will help you to arrive at your own claim. You need not follow another author. You can have your radical viewpoint, but make sure you back it up with at least three claims. These could be quotations or evidence that you have collected.
Brainstorming is the process of coming up with something original to say about the topic. Writing an essay is not merely regurgitating all that you have read. Instead what you have read should be a catalyst to your own original thinking. This can be done by examining the assumptions you make from several angles looking for weaknesses. Examine whether there are unconscious biases in the way you have put forward your assumptions. If you cannot think of enough to say, you may at this stage have to do a little more research.
Just like no builder ever thinks of a building without a blueprint, you should not think of writing an essay without an outline. The advantage of having an outline is that it allows you to spot weaknesses before committing them into the final draft. If you feel the arguments and evidence you have garnered is in thin in some area, you have a chance to bolster it up with a little more facts. When you do an outline, you will be able to spot which is your best paragraph and put it ahead of the others. The weakest arguments should be hidden in the middle of the essay. More readers are likely to remember the beginning and the end more than the middle.
Now to the essay itself. Start with the introduction. This is your chance to grab the attention of your reader; so make sure you have an interesting quotation or a startling fact or a paradox as your opening gambit. An introduction need be only a few sentences long. Too long an introduction will only make you lose the effect of the punch you have delivered. Jump straight away into the specifics and present your thesis without elaborating it in anyway. That you can keep for the body of the essay.
Make sure your paragraphs deal only with one idea at a time. The rest of the paragraph should be elaborations and arguments in favour of what you have said as your argument. The first sentence of a paragraph should be the most important sentence in the paragraph. Within the paragraph give quotations to support your claim, have ready counterarguments to nullify the criticisms that could logically come up, produce more evidence to support your statements and if possible provide another slant to the claim or thesis.
Your thesis should be divided into three paragraphs dealing with three different aspects of the claim. Each claim should be followed by the relevant supporting evidence, quotations, statistics or reasoning. Make sure you do not repeat one idea that has been already elaborated in another paragraph. Your thesis should be an arguable one and not a bare statement. Only then will you have enough to say.
The length of the conclusion will be decided by the length of the essay itself. If the essay is a short one of say 600 words, the recap of points should not run to more than couple of sentences. But if the essay is long and involved, it is worth summarizing what you have said. Do not repeat the same words. Instead reword it so that it sounds fresh to the reader.
The ending should not be abrupt like the banging of a door when a person exits from a room. You can use a quotation that is relevant, or a thought provoking remark or recommend a course of action to the reader. Make sure the conclusion is not lengthy. It should not be more than ten lines long. Say nothing new in the conclusion and do not repeat any idea word for word though they are all yours. Conclusions take effort but they are doable.