Business use of your home: must be used exclusively and regularly for your trade or business and your principal place of business. It is based on the percentage of your home used to conduct business, and you can deduct mortgage interest, homeowners insurance, rent, and utilities.
Business use of car: business part of interest on your car loan, parking fees, tolls, and mileage (2019 rate is $0.58 per mile)
CPE credits for professional license and license renewal fees
Business meals and entertainment: up to 50%
Medical and dental insurance premiums for yourself
Business equipment, computer equipment, and office furniture: can deduct the full purchase cost for any bought or financed after 2017
Legal and professional services: lawyers, bookkeepers, etc.
Partial cost of tax preparation related to self-employment activity can be included on Schedule C (line 17)
Half of SE tax you pay
Interest on loans used for business
Software purchased from January 1, 2003, to December 31, 2014, is eligible for a section 179 deduction
Transaction fees from payment processors