The Nazis gradually devised an electoral strategy to win northern farmers and white collar voters in small towns, which produced a landslide electoral victory in September 1930 (jump from roughly 3% to 18% of the votes cast) due to the depression. Refused a chance to form a cabinet, and unwilling to share in a coalition regime, the Nazis joined the Communists in violence and disorder between 1931 and 1933. In 1932, Hitler ran for President and won 30% of the vote, forcing the eventual victor, Paul von Hindenburg, into a runoff election. After a bigger landslide in July 1932 (44%), their vote declined and their movement weakened (Hitler lost the presidential election to WWI veteran Paul von Hindenburg in April; elections of November 1932 roughly 42%), so Hitler decided to enter a coalition government as chancellor in January 1933.
Upon the death of Hindenburg in August 1934, Hitler was the consensus successor.
With an improving economy, Hitler claimed credit and consolidated his position as a dictator, having succeeded in eliminating challenges from other political parties and government institutions. The German industrial machine was built up in preparation for war. In November 1937, he was comfortable enough to call his top military aides together at the "Führer Conference," when he outlined his plans for a war of aggression in Europe. Those who objected to the plan were dismissed.
i got this from- http://www2.dsu.nodak.edu/users/dmeier/Holocaust/hitler.html
hope it helped
I am no expert on this, however I would look in to the hyperinflation in the German economy during the rise of Hitler.