http://www.murthy.com/2015/02/11/h1b-cap-season-reminder-multiple-h1b-filings-for-same-beneficiary/ warns…

…multiple H1B petitions filed by different companies for the same position at the same end-client with the same beneficiary.

—(I think Liu Ling shared ..)
To increase the lottery chance, find as many sponsors as possible. Many Indians do that. Must pay the cost each time. About $4k for each petition.