If you are operating as a sole proprietor (reporting on Schedule C), the potential expenses deductible from your gross income are too numerous to list. The publication at the link below is a good place to start.
The IRS also has a web site for self-employed individuals.
just about everything that is business related though the deduction s for things like gifts, meals and entertainment are limited. capital expenditures must be capitalized and depreciated but bonus depreciation should allow full deduction in year acquired/placed in service. the will be limits on depreciation for certain vehicles. this is just a general summary.