There is a very good IRS publication that spells out deductions for military personnel, IRS Pub. 3, at this link:
https://www.irs.gov/pub/irs-pdf/p3.pdfThe deductible items are claimed as a Miscellaneous Itemized deduction, subject to a 2% of AGI floor on Schedule A. Only the amount of such deductions that is more than 2% of your adjusted gross income is actually deducted, and you get no tax benefit from itemized deductions until all of them added together are more than the standard deduction for your filing status.
2015 Standard Deduction
Taxpayer under 65, not claimed as a dependent
$6,300 for Single
$12,600 for Married Filing Jointly, or Qualifying Widow(er) with dependent child
$9,250 for Head of Household
$6,300 for Married Filing Separately
For over 65 or blind, add $1,250 for each instance or add
$1,550 each instance if single and not a surviving spouse.
Note that gym membership is not deductible and neither are haircuts. See IRS Pub. 529
IRS Pub. 529, Miscellaneous Deductions,
https://www.irs.gov/pub/irs-pdf/p529.pdfList of Non-Deductible expenses starts on page 14