Well, it's not easy due to the cultural differences, including humor. When I was in the US I got to make very few friends but that was because they were interested in different cultures as well. 

I remember I had this friend in Austin and she was very interested in Brazilian culture, in our language, food and people and she's constantly travelling to Brazil so we could sit and talk for hours and hours. She once took me to a party at her friends' house and dammit, I felt so lost and like an alien, I could not interact with them because they were not interested in me at all, I mean, they were nice and polite but other than that, no matter how hard I would try to talk to them, we wouldn't just click. They never cared to ask how I was enjoying the US nor they asked about about me or my culture and they were talking humors all the time between them that I could not find funny but they were laughing their ... off hehe. 

So, my tip would be: Find Americans interested in your culture. How is that possible? Well, couchsurfing, meetup.com and believe me, dating apps! While I was in the US, I had these dating apps that were very handy because since I stated in my profile that I was a visitor from Brazil, only people who were interested about it came to talk to me and offered to show the city, to go for a walk and etc and it was only a friendly date :) 

I would also recommend to get enrolled into a course, activity or something. Maybe dance, cooking classes or anything that you'd have to be in touch with other local people.