The Wall Street Crash in 1929 caused huge economic problems for Germany. With millions unemployed, German citizens lost faith in the Weimar Government. Hitler was able to exploit this by promising to rebuild a strong Germany.
Hitler was a charismatic and powerful public speaker.
Goebbels' propaganda campaign was very effective and it won support for the Nazis. The Nazis targeted specific groups of society with different slogans and policies to win their support.
Using intimidation and force to attack opponents.
Once elected chancellor, Article 52 of the Weimar Constitution gave Hitler the power to dissolve parliament and create the Nazi state.