If you are looking for a job while you are in Pakistan, you can use online resources however search engine returns so many results for job queries that it’s confusing sometimes. I am mentioning few websites that are mostly used to search jobs in United States that lists many jobs to chose from. Please bear in mind that these are the most famous online job websites in United States.
People in United States when looking for a job, refer to these website and they most of the times get a job. Before applying make sure to read the full description. If they says that they are hiring a person from within United States then there is no point of applying. Also if they say that they are not sponsoring any work visas then don’t bother applying as they might not be able to offer a job to people outside of United States.
I do not want to disappoint however the most wanted jobs where people are issued a work visa overseas is the technical fields i.e. computer science, engineering, medical doctors, specialized in accounting/finance, a cooks with some international specialty cooking etc. If you have education that is not in demand, i.e. MBA and working in a office etc then there are almost no chances for you to get a job in United States while you are in Pakistan.