Congress has passed the massive Republican tax bill, and President Donald Trump signed it into law before Christmas.

For taxpayers who itemize their deductions, that could mean an increased tax bill in 2018. But there are some things you can do now to prepare for the changes, including maximizing your 2017 tax deductions.

Under current tax law, you can deduct taxes paid to state and local governments, including property, income, and sales taxes. But the new law caps the deduction at $10,000, either for property taxes, state and local income taxes, or sales tax.

Homeowners whose property taxes are more than $10,000 – and not subject to the alternative minimum tax – could save more money by paying next year’s bill by Sunday, the day before the new law takes effect, if their local government takes it.

That way, you can get the deduction for that payment when you file your 2017 taxes - especially useful for homeowners in states with relatively high taxes, like New York, New Jersey, and California.

Deducting the full amount of your current property-tax bill in 2017 may provide an even larger tax benefit if your tax rate goes down next year under the new plan, according to the experts at TaxAudit, an audit defense service.

What are property taxes?

Property taxes are just that: taxes you pay on your property.

There are two kinds of property taxes, depending on the property's mobility:

  1. The real-estate tax: for property that can't be moved, such as a house or land.
  2. The personal property tax: for property that can be moved, such as an RV or a plane.

To get the property-tax deduction, you have to itemize your deductions.

How do I pay property taxes?

Property taxes are administered on a local level, so to pay early you'll have to check with your county to see how to do so.

For example, the New York City Department of Finance's page on property taxes explains how residents can pay electronically, by mail, or in person at any of its business centers.

But keep in mind that if you own a home, your mortgage lender may pay your property taxes from an escrow account.

Unfortunately, you can't pre-pay SALT anymore

We originally suggested that it may be worth it for some taxpayers to prepay their 2018 state and local income tax liability this year to maximize that deduction as well.

But that's no longer possible: The version of the tax bill that became law says state and local income taxes paid for any tax year beginning in 2018 will not be deductible on your 2017 taxes.

"As the Tax Cuts and Jobs Act seeks to simplify the tax code, a last-minute provision closed a potential new tax-planning strategy germinating before the bill even passed," Nicole Kaeding, an economist with the Center for State Tax Policy at the Tax Foundation, said in a post.