In What Ways Did the Nazis Treatment of the Jews Develop in the Years 1933-1938?

Nazi party solidification is the only answer. If Nazis had the power to treat the Jews as horribly as they were by 1938 starting in 1933 they would have, but they did not have the backing or enough support do so yet. Over the course of these years the party rooted its power structure, blasted antisemitic propaganda and systematically jailed their opposition. As they did this over this time span they were able to increase and worsen their harassment of Jews.They needed the either the support or the complacent obedience of the German people and over this time period they won it.
In short, anti-Semitic propaganda fueled by Hitler's influence. Hitler believed that Jewish people were trying to control the country through business and finance, so he strongly urged people to ostracize and pretty much bully Jewish people. As Hitler's influence became more solid, treatment of Jewish people in Germany steadily worsened.

Guessing you are asking about in Germany. Well for starters 1933 was the year that Hitler and the Nazi party replaced the Weimar Republic. Nazi rhetoric blamed Jews for such things as the loss of WWI. The Jews were the Nazi scapegoat and their chastisement provided solutions to Germany's problems. Over the course of these 6 years conditions worsened for Jews and the Nazis solidified their hold. The highest % of votes the Nazi party every received was somewhere in the 40s, but due to Germany's multiparty system this was a clear majority. 33-39 served as a period of gradually easing Germany into supporting the Reich. In addition the party eliminated opposition and bombarded the public with propaganda, usually extremely antisemitic. This led to public antisemitic outbursts such as the events of Kristallnacht in 1938. Originally just political dissidents were sent to concentration camps, but as power was solidified and the opposition was ousted the worst case scenario came to fruition for the Jews. First mass ghettos, then mass camps, then mass extermination....