1. Valid Passport: Your passport should be valid for at least six months beyond your intended stay in the United States. It should also have at least one blank visa page.
2. Nonimmigrant Visa Application (Form DS-160): Fill out the online nonimmigrant visa application form (DS-160) accurately and completely.
3. Passport-sized Photos: Provide two recent passport-sized photographs that meet the specific requirements set by the U.S. embassy or consulate.
4. Proof of Travel Intent: Show evidence of your intention to travel to the United States for tourism purposes, such as a detailed travel itinerary, hotel reservations, or a letter of invitation from a U.S. host (if applicable).
5. Proof of Financial Means: Demonstrate that you have sufficient funds to cover your expenses during your stay in the United States. This can include bank statements, pay stubs, or other financial documents.
6. Interview Appointment: Schedule an interview appointment at the U.S. embassy or consulate. In some cases, a visa interview may be waived for certain applicants based on their age or other factors.
7. Supporting Documents: Depending on your specific circumstances and the requirements of the U.S. embassy or consulate, you may need to provide additional documents. These could include proof of ties to your home country, previous travel history, employment or educational records, or other supporting documents to demonstrate your eligibility for a tourist visa.

The initial period of stay granted on a tourist visa to the United States is typically up to six months. However, the immigration officer at the port of entry ultimately determines the length of stay allowed based on the purpose of your visit and your individual circumstances.

The processing time for a U.S. tourist visa can vary depending on various factors, including the workload of the U.S. embassy or consulate where you apply. In general, it can take anywhere from a few weeks to a few months for the visa to be processed.