The Bolsheviki overcame the provisional government because of the following factors: their revolution was planned, not a disorderly revolt of unled people; they had a visionary leader in Lenin, newly arrived from Switzerland and with a clear message, a strong motivation and strength of character; the provisional government were, and represented more the comfortable landowners, not the ordinary people who were seriously undernourished and badly treated, worn out by wars where they were ill-equipped and poorly maintained in provisions and aid.
The Bolsheviki knew and understood the peoples' strong need for "peace, land and bread" and so the movement was strong enough to overthrow the provisional government easily.