The first of all when you decide to travel to USA, you must to get a visa/ a residence permit, because USA isn’t in an European Union( for example: you are an European citizen).
The second thing that you have to do is to prepare some kind of plan which might to include what places you want to visit. You have to decide how many times you will be in USA. According your times, you have to make a decision which are your priorities places that you want to visit first and have to write a plan for every days in USA.
If you are the person loving nature I would recommend you starting to visit
“Yosemite” National Park. It is famous for its many beautiful waterfalls, as well as its thick pine forests. This is one of America’s most attractive natural landmarks. The park is magnificent in all seasons.
Either you could visit “Yellowstone” National Park. With its untouched typical North American nature. “Yellowstone” will bring you back in the years when the first Europeans had come. There are hundreds of geysers in “Yellowstone”, but the most respected is the Old Faithful Geyser, which during the eruption can emit hot water more than 50 meters.
If you are the person loving a city life, I would recommend you to visit “Time Square”. This is the most famous place in the United States. You know better than anywhere you will feel the spirit of the country of unlimited possibilities. Hidden skyscrapers with glass facades, dozens of billboards and video screens, thousands of passers-by passing by all the nationalities living on our planet, and the immense yellow New York taxis. If you visit Time Square, you can reasonably claim that you are in the center of the world.
Either you could visit Universal city. It would be a big omission if traveling to America does not turn to California. An even bigger omission would be if you do not visit Universal City. This is a whole movie town, located in the heart of the second largest American megapolis- Los Angeles.
That are some proposals for visit, according your personality, you have to make decision what you would want to visit.
I would wish you the best, most incredible trip than now! Have fun!