The deduction for sales taxes consists of two parts:
1. General sales taxes paid. TurboTax calculates this part of the deduction based on your income, number of people in your household, and local sales tax rate.
2. An added deduction for certain major purchases. Automobile purchases (even used ones) falls in this category, so you'll want to input that data in TurboTax. Taxes on your rent does not fall in this category; it's covered in the general sales taxes part.
Keep in mind that you can deduct either your state income taxes or sales taxes. Most people living in states with an income tax end up taking the income tax deduction because it's a bigger deduction.
This is one itemized deduction out of many. The best way to make sure you claim all itemized deductions is to go through all TurboTax interviews under Deductions & Credits.