Most of the policies that FDR employed increased the severity of the Great Depression.
Bubble in commodities like grain, cattle etc which grew during the roaring 20s based on speculation and probably market manipulation by the federal reserve.
When the bubble burst in 1929 FDR vowed to fix the market, and so when he came into power he instituted a series of price fixing policies (aka creating artificial shortages) in order to "help the farmers and investors" as there was now an over abundance of stock causing prices to plummet dramatically.
(now if you weren't an inbred studying history, and instead studied something useful, you would realise the insanity of these policies)
Farmers were forced to kill their cattle, and burn their crops as it cost too much to keep on hand, and thanks to price fixing, they could only sell a fraction of their stock. So while people starved in the streets, farmers were destroying their food. This lead to the infamous "dustbowl" in the united states.
READ ABOUT BROKEN WINDOW THEORY and then realise the insanity of keynesianism.
There have been bigger crashes than the crash of 1929, but the severity was due to the Governments reaction to the crash.
FDR also temporarily banned and confiscated gold (aka literal theft of people's wealth), and abandoned the gold standard causing the usd to inflate relative to gold from 20(or so) usd to 35 usd, destroying saver's purchasing power.
FDR took over many private production industries, which meant that businesses couldn't develop products which people wanted. The government more or less paid people to dig ditches and then fill them in again, leaving no positive productive externality to society (like when you produce a car for some one, there is a transfer of value, and that car then decreases the value of all other cars and second hand cars on the market (less demand), allowing for poorer people to buy and consume).
On my phone cbf rereading for mistakes etc