The language of hate
How do you make one group of people hate another group of people they have never met? You use language to do it. The vast majority of Americans have never met someone who follows Islam. Yet we constantly see right-wing politicians and pundits warning of Sharia law, or that Islam is a warlike religion by taking carefully selected certain passages out of the Koran out of context, or quoting the most reactionary of Islamic clerics. It is no different than what the Nazis did running up to WWII with people of the Jewish faith.
Newspapers in Germany, above all Der Stürmer (The Attacker), printed cartoons that used antisemitic caricatures to depict Jews. After the Germans began World War II with the invasion of Poland in September 1939, the Nazi regime employed propaganda to impress upon German civilians and soldiers that the Jews were not only subhuman, but also dangerous enemies of the German Reich. The regime aimed to elicit support, or at least acquiescence, for policies aimed at removing Jews permanently from areas of German settlement
Make the group you want people to hate different and subhuman through caricatures. We see this again and again through history around the world. In the way African Americans, Irish Americans, Native Americans, Japanese Americans and the list goes on, have been portrayed throughout the history of the United States.