What were some of FDR's major accomplishments?

Basically, FDR did two things.  First, he helped reduce
the impact of the Great Depression.  Second, he led the US during most of World War II. 
This means that he was president during two of the biggest crises in US
history.

People often say that FDR ended the Depression
with the New Deal.  Most historians do not agree with this.  They say that the coming of
WWII ended the Depression.  However, FDR's policies and his personal abilities clearly
helped to stabilize the economy after 1933 and prevent it from getting
worse.

Before and during WWII, FDR forged an alliance with
Great Britain and (less so) with the USSR.  He skillfully managed this alliance during
the war and he was in overall charge of the war effort.  his work clearly helped the
Allies to win the war.