The good news is that from a legal standpoint, Pakistan and America aren't too far separate and both use Common Law for their court systems (The big difference is the ~250 year divide when the U.S. broke with British and added a codified constitution to further govern it's laws (the UK is today one of the few countries with out a codified constitution in the world).
The thing about America that baffles a lot of people is that the U.S. is freakin' huge! It is the 3rd largest country by land area (Behind Russia and Canada) and by population (Behind China and India). There are states that dwarf countries and people from certain states get stereotyped for certain traits like many countries do (I.E. All Californians are far-left Hippies, All Texans are gun carrying cowboys, and All Floridians are either old, crazy, or both. In reality there is a sizeable conservative base in California that is mostly found away from the coastal urban areas, Texas has very liberal areas in Austin, it's capital, and El Paso and has been turning less reliable for the conservative politics. And Florida isn't any more crazy than any other state in the union, it's just got some quality journalists and the "Sunshine Law", their equivalent of the Freedom of Information Act, renders most state government actions very open and accessible to the public).
The big challenge for many people not familiar with the U.S. is that they can't comprehend that sheer vastness of size, though regional cultures do tend to grow develop in all nations, it's just very prominent in the U.S. because of the size of the region.
I've found that to best understand a foreign country, it's best to understand why the things they enjoy in their culture are enjoyed so much. For example, Americans often get stereotyped as being loud and rude by non-Americans. A lot of that is because Americans have a tendency to be open with what upsets them in part because Freedom of Speech Laws in the U.S. are some of the most liberal in the world (Which makes Americans very open with each other about what's bothering them... and very honest about it). The Rudeness stems from the fact that until the internet allowed communications with people from around the world, Americans didn't do much foreign travel (Only about a third of all Americans hold a valid passport... with an equal amount having never held one in their life and the rest just never bothering to renew it.) and weren't used to the idea that what they see as normal others will see as rude (It's not just a big deal rude too. In Japan, leaving a tip for the waitress is considered a huge insult. In the U.S., not leaving a tip is considered highly rude, even if the service was terrible.).
A lot of behavioral attitudes of any nation are found rooted in their nation's history and identity. For example, one thing a lot of foreigners can't understand is the American Gun culture and specific members within that culture stating they keep their guns in the event of the U.S. Government going rogue. The response being that "they can't take on the greatest military power in the world", forgetting that the U.S. was birthed from a war where they not only did just that, but won (and that war was started when the government came to seize weapons from what was... at the time... the edge of the frontier...).
One option you could go with is to make your PoV character(s) Pakistani-Immigrants (American's love an Immigrant's tale because they usually tend to show America as a place with faults but one that is still filled with promise of a better life). That way you can have a voice for your own perspective and to help you focus your understanding and expectations in contrast to what you see. A big thing to remember is that film and TV depictions of things are not always accurate nor as exciting as depicted.