Every IRS audit is different, but the most important item is a
contemporaneous journal (a diary). This is maintained in real
time, not just before tax time if you need it. In it, you record
date and facility visited, who you went with, how much you bet
and won. An online betting facility will give you an annual statement.
You should save your annotated programs which will help confirm
your attendance. Losing tickets are pretty much worthless - anyone
can pick them up and, if you were really trying to substantiate losses,
you'd need a truckload of them.
It's important that all your winnings be reported. If you report
only enough losses to negate your $3,000 signer, they will immediately
wonder why you never won any other bets. And, whether or not it
was a signer or tax was withheld, the winnings are taxable, even
the $3.20 Goiko win ticket.
I ought to make up a permanent page on this matter - the subject
comes up a lot.
