Please prepare all your documents and apply online visit https://ceac.state.gov/genniv/
All information is available online,fill the online application which may take upto 40 mins. or more to fill,keep your soft copy of your photo as per guidelines,pay fees at commercial bank,schedule your appointment after these formalities are complete.
1. Keep Yellow payment slip (commercial bank) with you during the day of interview.
2. Carry all your original documents and passports old & new.
Documents required are :
1. Oroginal passports
2. NOC from your Employer
3. Bank Statement
4. Invitation Letter
5. Travel Plans (Not very important but better to keep handy)
Please do not furnish any false information.

All The best