When Lenin returned to Russia on 3rd April 1917, he announced his ideas (his April Theses). In the short document, there were then points being made.
1. The war being fought is an imperialist war and a peaceful, democratic ending to the war will only be possible if capital is overthrown. With "particular thoroughness, persistence and patience" this has to be explained to the masses.
2. The unfolding revolution is passing from the first stage where power was put into the hands of the bourgeoisie to the second stage where power must be placed into the hands of the proletariat and the poorest section of the peasants.
3. No support for the provisional Government, "a government of capitalists".
4. Recognition that the Bolsheviks were a small minority in the Soviet and therefore it was necessary for a "patient, systematic and persistent explanation" of the errors of the other parties. At the same time to preach of the need to transfer "the entire state power to the Soviets of Workers Deputies."
5. Not a parliamentary republic but a republic of Soviets of Workers', Agricultural Labourers' and Peasants' Deputies. No standing army but an armed people. Elected officials subject to recall and paid the same as a competent worker.
6. Confiscation of all landed estates and nationalisation of all lands in the country.
7. Banks to be amalgamated into a single bank under the control of the Soviet of Workers' Deputies.
8. Social production and distribution of products under the control of the Soviets.
9. Convocation of a Party Congress. Change Party programme on the imperialist war, the state and the minimum programme. Change of name to Communist Party.
10. A new International.
These ten points laid the basis for the October Revolution which would not have been successful without the leadership of Lenin. They confirmed the inability of capitalism to take society forward and therefore the need to move to the stage of the proletarian revolution. This point brilliantly confirmed Trotsky's Permanent Revolution. Production of wealth and finance to be in the hands of the working class through its democratic organisations. A break with the Mensheviks and the formation of a new Party to fight for power. A break too with the reformist Second International and the creation of a new (Third) International.
Lenin reshaped the Bolshevik party into one with a firm platform that appealed to peasant demands. Lenin promised distribution of land among peasants, socioeconomic reforms, and an end to Russia’s role in WWI. While the peasants felt that Lenin was on their side, he was less concerned with giving peasants what they wanted than he was intent on encouraging them to follow his leadership. Through this conduit, Lenin gained the power he needed in order to render the Mensheviks and the Socialist Revolutionaries impotent; while Bolshevik efforts to mobilize were not unknown to members of the Provisional Government, little was done to undermine their plans.
Lenin thought his chance had come in July. There was an uprising against the government and the Bolsheviks took advantage of the situation and supported the protesters. In the end though, the uprising was suppressed and many Bolsheviks, including Trotsky were imprisoned. Again, Lenin left for overseas. The provisional government tried to win more support by resigning and placing Kerensky as the new prime minister of a new government, mainly made up of Mensheviks and social revolutionaries. This satisfied the people at first, but soon the armed forces tried to overthrow Kerensky. Worried, Kerensky turned to the Bolsheviks for support. He released Bolshevik prisoners and gave them much power. This enabled the Bolsheviks to start taking control. Realising another chance had came, Lenin wrote to his comrades, telling them to organise a second revolution.
In conclusion, I believe that Lenin was absolutely vital to the October revolution because it was Lenin who won that struggle, who secured the Russian Revolution as a people’s revolution. His leadership during that year – his propaganda in Pravda and it was the Bolsheviks who defeated Kornilov in August and took over Petrograd Soviet in September, the Bolsheviks became more and more popular and then in November they organised a mass uprising – which established it as a true popular revolution. On the other hand, Lenin was the leader – he got to make the speech announcing the new government on 8 November – but it was Trotsky who did the work. It was Trotsky who ran the Red Guards who defeated Kornilov – Trotsky who took over the Petrograd Soviet by becoming Chairman – Trotsky who persuaded Lenin to mount the November revolution, and then who organised the Red Guards who won it.