Firstly, you have to create a thesis statement that answers the question. An example would be "From the beginning of the Bolshevik rule in 1917, Soviet foreign policy was based on the need to survive rather than being dominated by ideological concerns. When applicable, foreign policy attempted to accommodate the socialist ideologies but as conflict arose the Soviet party had to compromise its principles in order to survive."
After this, you must form your arguments for the body paragraphs. It is easy for this essay to split it into 3 body paragraphs each delving into the time periods:
Early Bolshevik rule (1917-1920): Purely practical goals as Lenin attempted to maintain his hold on Russia, It was imperative to the Bolsheviks survival for Russia to withdraw from WW1 as Russia had been brutalised by famine and lack of resources. You could discuss the peace treaty of 'Brest Litovsk' where Lenin overruled Trotsky, demanding peace with Germany at ‘whatever the cost’, while also disregarding Bukharin’s and the socialist view of a ‘revolutionary war’. In this time period, Poland's leaders also captured Kiev (capital of Ukraine). Following this capture, some in the Soviet Government began a discussion of the ‘revolutionary war’, the orthodox Marxist view that revolution in the advanced states of Europe was essential for the success of the revolution in the USSR. It was believed that an advance against Poland would possibly spark a revolution in Germany. Russia was unsuccessful and the Soviet’s defeat by Poland put an end to the imminent hope of revolution spreading across Europe.
The 1920s: A two-pronged approach towards foreign policy developed in the early Soviet state, on one hand, traditional diplomacy aimed at securing a ‘normal’ relationship with the outside world, and on the other hand, a drive to foment socialist revolution outside of Russia. Here, discuss the Comintern and its effects on the Soviet Union and Anglo relationships (mention Zinoviev letter)
The 1930s: The fundamental aim of Soviet foreign policy in the 1930s was to avoid being drawn into a war. Stalin was aware of the dangers presented by the growth of Nazism in the west and Japanese militarism in the east. Discuss collective security, and most importantly, the Nazi-Soviet pact of 1939. Stalin despised all the Nazism stood for; it was the ideological antithesis of socialism. Hitler also despised Bolshevism, believing that it was a product of Jewish conspiracy. For Hitler there was one aim, he wanted to ensure that he would not have to face another two year war which had been disastrous for Germany in the first World War. Stalin’s motives were equally opportunistic, a deal with Hitler would ensure that Germany moved west and that a large conflict would ensue which would weaken both Germany and Western powers, more importantly it also gave the Soviet Union time to strengthen its military for the inevitable struggle with Germany.