I would start answering this question by reading the question carefully and ensuring to know which tsars were in power during these time periods. Since this is a 'how successful' question it can go one of two ways. Either the for-and-against method, or splitting it into three opposition groups e.g. populists, Marxists and the intelligentsia. With this split opposition method, you can state what each group did that successfully opposed the Tsar, for example the assassination of Alexander ii in 1881 was a success for the populists, however in rebuttal, Alexander iii took quick action through increased censorship and exiling radicals.You would carry this on through your whole essay, making sure that your paragraphs are not too long and do not include information that is not needed, as this will waste time. When you reach your conclusion, each of your paragraphs should already contain a mini conclusion, making your main conclusion a summary of the mini ones, and not of the examples themselves.