I bought a car last year and entered the sales tax information. However, my refund did not increase. Was something incorrect?

Sales tax is an itemized deduction. You are allowed to deduct state and local sales tax OR state and local income tax whichever is greater. If the state and local sales tax is greater, then that is added to your property taxes and any other SALT taxes up to a maximum of $10,000 for the total of all those types of taxes. If all your itemized deductions are more than the standard deduction, you may get a tax benefit. The SALT limitation and elimination of some other itemized deductions along with the nearly double standard deduction in 2018 means many filers will not get a benefit from itemizing deductions. Here are the new standard deductions: 

Single - $12,000 add $1,600 if age 65 or older

Married Filing Separately - $12,000 add $1,300 if age 65 or older

Married Filing Jointly - $24,000 add $1,300 for each spouse age 65 or older

Head of Household - $18,000 add $1,600 if age 65 or older