Your refund will remain the same until the total of all your itemized deductions total more than the standard deduction. The standard deduction doubled a year ago from what it was in prior years so many filers now find that the standard deduction is more than the itemized deductions.
You can deduct either sales taxes or state income taxes if your state has a state income tax but not both. You have a choice to use the table for sales tax deduction based on your income or to enter all your receipts if they are more than the table amount. There is a $10,000 limit for the total of sales or state income tax and property taxes.
See this for a description of what is included in itemized deductions: https://turbotax.intuit.com/tax-tips/tax-deductions-and-credits/what-are-itemized-tax-deductions/L1p...
