Easy. Your passport. Your entry visa...apply through your travel agent, they have connections to companies that will arrange this for you through the nearest Indian consulate. Make sure you have the address of your host or sponsor handy. Bon voyage!

first of all,what are you taking to india? if you have nothing out of the ordinary to declare,then you do not need additional papers for customs.the customs paper that's given to you on board the aircraft will suffice.exporting stuff out of india is trickier.you need import/export license from the u.s.gov't.and keep all your documents original.the single most important thing you have to be very careful with is to check your merchandise before shipping.i have done business with the indians in the past and was very disatisfied with the way they conducted business.these guys would deliberately ship the wrong set of goods to you.now in order for you to get back your money,you have to re-ship the goods to india and you pay for the shipping.remember,the money is paid to the bank before the goods are shipped. be warned,customs in india are very strict.you are allowed 2 lt.of liquor,200 cigarettes and 50 cigars per person.for every additional litre of liquor you take,you pay a fine of u.s.$100:00 even though it cost only about $27:50/litre. almost any product you plan to import from india can be had right here in the u.s.for a fraction of the cost.