To get H1B from OPT, could you please tell me what kind of documents I should prepare?

I'm still looking for a sponsor and I want to prepare all the documents.

Could you give me a list of requirement to apply for HIB?

Thank you very much for your time and help.

Get a job offer first... the employer must handle this issue until the application have been approved, then notice of approval will be forwarded to you together with instructions from the employer's company.. then you can contact the nearest US consulate to apply for H-1B.