Lenin won and consolidated his power through the Russian Civil War, in which his Red Army, led by Bolshevik revolutionaries but populated in part by conscripts, defeated the enemies of the Revolution, who ranged from moderate socialists to royalist reactionaries. In the process, he used, and would continue to use terror to maintain and strengthen the state. Lenin established a secret police organization called the Cheka, which was instrumental in the so-called Red Terror in which thousands of state enemies were arrested and either executed or exiled.
Lenin continued to use terror throughout the rest of his political life. After victory was achieved in the Civil War, he turned to dissident factions within the Bolsheviks, sending many of them to forced labor camps, and he brutally cracked down on peasant protests. But he also won the loyalty of the Russian people, specifically the peasants, by empowering them to occupy lands formerly held by nobles. He also proved flexible and willing to compromise when he implemented the New Economic Plan, or NEP, which allowed for some market reforms. And through his reforms, he provided many Russian people, including women, with an education that helped to create a class of bureaucrats that were loyal to the state.
But ultimately, Lenin seized, maintained, and consolidated power through force and terror. While his efforts in this regard would pale in comparison to his successor, Joseph Stalin, it could also be argued that they paved the way for them.
No, it's not just Red Terror. It is a major factor though.
1)War Communism, but when that began to flop, due to the unpopularity of the Bolsheviks, Lenin introduced the
2) NEP. Whether he was following Marxist ideals or not, we cannot say - he died only six years after taking control.
3) He also had the brilliant Trotsky, and Trotsky had a way with people, and could easily manipulate the government into the way he wanted to mould it.
4) Propaganda. Leningrad? Oh please.
That's all I can thing of.