The issue here is that itemized deductions are unlikely to exceed the standard deduction for a resident. So in essence, nothing is deductible (for most residents). Sorry.
Even if you have enough "business expenses" you need to be a business owner, not an employee (as residents are.) So unless you've got time to run a business on the side (such as moonlighting), not much to deduct there.
The good news is you don't make much money as a resident either. So you really don't pay much in tax anyway. Your biggest tax will be social security, which you can't get out of no matter how many deductions you can accrue.
Consider this:
A married resident with 2 children makes $45K a year. His standard deduction is $11,600. He gets 4 exemptions worth another $14,800. He now has a taxable income of $18,500. Tax due is 1934. Child tax credit is $2000. Tax bill? You GET $66 from the government. This resident wouldn't even be paying taxes without ANY deductions. Even if you're single with no dependents you're still only looking at paying $5050. Compare that to the tax bill of a single attending making $200,000 of ~ $50,000. That, of course, doesn't count state taxes or payroll taxes, which could add up to another $30K.
My point is that residency isn't the time to be worried about decreasing your tax bill by a couple of bucks. The single best thing you could do to lower your tax bill would be to get married and/or have a kid. Whether that'll increase your after-tax after-expense income, of course, is another question entirely.