First of all, read the question twice. Then, using a highlighter, highlight the key words of the question (one to four terms which are at the core of the question. E.g. "Analyse the success of Alexander II's reforms in the years 1855-1880"). From here, there are different methods of brainstorming ideas. I personally like to draw a line from these key terms and then write my ideas about them, like a spider diagram (e.g. "what is meant by analyse?" "which reforms did he have?"). Then I continue the spider diagram using facts and statistics on the second 'layer' of the diagram.
So now you should have closely looked at the ideas surrounding the question AND have some facts to support your points. Now summarise these in a few bullet points (2-5 depending) and think closely about the order you introduce your points in - often, marks are awarded for how you structure your essay. This will keep your essay organised and keep you on track.
Now for your introduction! Give one line to set the scene - e.g. "Alexander II set forth his ambitions plans for reform after succeeding his father Nicholas I on the 2nd of March 1855." - here you can flex some of your facts. Next, you want to establish that the matter at hand is hotly debated (e.g. "Historians are yet to arrive at a consensus regarding the success of this scheme of reforms.") Then you want to pick a strong, nuanced line of argument and stick with it. 'Nuanced' means that you may agree with some aspects of the question, but not others. (e.g. "Yet, it is clear that some had an extremely positive impact, such as his changes to the military, whereas the majority of his social reforms failed to succeed as he intended").
You will carry this strong, nuanced line of argument throughout your main essay, using the bullet points you made in your plan.
Remember:
DON'T use "I" or "Me": Write in the third person. This gives a more sophisticated, 'historian' feel to your essay and will impress examiners. There are ways to get around saying "I think..." or "In my opinion" (e.g. "It is evident that...", "One could argue...")
Always offer a counterargument: essays are debates. If you offer one argument, think about how another fact or perspective may be more accurate, and debate yourself within the essay. This is great analysis. Some examples of phrases to help you: "However, this argument may be flawed as...", "The [event] sheds new light on this line of thought..." , "Yet, this interpretation is not convincing as..."
Always support your arguments with facts/stats: you'll not just be marked on how good your debates are, but also on the evidence you provide. This will make your argument more convincing and score you more marks. Make sure you revise a range of facts and statistics to support your arguments. Your spider diagram plan will help you find facts to use.
Check SPaG: Make sure you allow yourself a good 5 minutes to read through your essay after you finish it. You will pick up on silly SPaG errors (Spelling, Punctuation and Grammar) which cost you marks.
ALWAYS REFER BACK TO THE QUESTION! Every single sentence you write should in some way relate directly to you discussing the question. No tangents, no ranting, no rambling - just direct, nuanced analysis and hard evidence to back it up. Using the words of the question to structure your opening sentences of paragraphs will help keep you on track.
Conclusion:
So finally you're ready to finish this essay. Please, PLEASE do not rush the conclusion. An evaluative conclusion will push you up into the higher bands - some exam boards refuse to give a high band mark if there is no conclusion, or if the conclusion is not extensive enough. This is where you summarise the points you have made, relating back to the strong line of argument you established in your introduction. Explore how you agree with one aspect of the question, but disagree with another. End strong and confident.
And then read through for SPaG errors, as previously discussed.
Make sure you keep track of the clock!
And be confident - if you've been tutored by someone like me, who studies History at the university which is ranked No.1 in historical research, you'll be more than prepared to answer any question the examiners throw at you.
[I also tutor Spanish and English!]