A year ago, it was difficult for taxpayers to do last-minute tax planning because of uncertainty surrounding expiring tax breaks from the Bush era.

Lawmakers were at loggerheads on which, if any, deductions and credits to keep and whether to let tax rates rise.

This year, uncertainty isn't a problem. The American Taxpayer Relief Act, signed into law in January, has left taxes much the same for households with incomes less than $250,000. And for those with income above that, the tax landscape is clear, too: They will owe Uncle Sam more.

"High-income taxpayers have tax increases coming at them from multiple directions," said Tim Steffen, director of financial planning at Robert W. Baird in Milwaukee. "It's going to be some real sticker shock for them when they start looking at their tax returns a few months from now."

Congress raised tax rates on regular income and capital gains for the affluent. It also created a new tax for them on investment income as well as adding an extra Medicare tax on high wages. And the well-off will once more see their itemized deductions reduced as income goes up.

With Maryland having the nation's highest median income, these changes likely will affect residents here moreso than many in other states.

There still is one uncertainty, though, at this late stage about taxes — the start of the tax season. It had been scheduled for Jan. 21. But the government shutdown in October interrupted IRS preparations for the coming season, and the agency said the launch of the tax season will be no earlier than Jan. 28, but no later than Feb. 4.

For taxpayers, here are some changes to be aware of for the 2013 tax season, as well as some moves to consider that might reduce how much you owe:

The return of higher rates The lower tax rates on regular income introduced during the Bush administration remain intact. But the wealthy will see the return of the top tax rate of 39.6 percent, which had disappeared for years. This rate applies to taxable income above $400,000 for singles and $450,000 for married joint filers.

Most people don't fall into this category. But those who do might want to consider shifting more toward nontaxable income, such as tax-exempt bonds, said Mark Luscombe, principal analyst with CCH, an Illinois-based provider of tax information.

Or, if self-employed, taxpayers can try to get below those $400,000 and $450,000 limits by postponing income into next year, such as sending bills to customers early next year, Luscombe said.

Taxpayers in these income thresholds also will see the rate on long-term capital gains go up from 15 percent to 20 percent.

Those in the two bottom tax brackets — 10 and 15 percent — will continue not to be taxed on capital gains. Everyone else remains taxed at a rate of 15 percent.

Taxes to support health reform The well-to-do will be kicking in more under two new taxes that were part of the Affordable Care Act, better known as Obamacare.

Workers already pay 1.45 percent of wages for Medicare. But high-earners this year started paying an additional 0.9 percent on wages exceeding $200,000 for singles and $250,000 for joint filers.

Taxpayers at those income levels also will be subject to a new 3.8 percent tax on net investment income, which includes dividends, royalties, rents and capital gains.

This tax applies to whichever is less: the amount of net investment income or adjusted gross income over the $200,000 and $250,000 thresholds.

With this 3.8 percent tax plus regular capital gains tax, it's possible that some taxpayers will pay a rate of 18.8 percent or 23.8 percent on investment gains.

It gets complicated.

"At the end of the day, what's happened is it's become very difficult," said David Rosen, director of tax services at RS&F, an accounting and business consulting firm in Owings Mills. "Where I used to be able to go through a person's situation and figure out in my head what their next year tax will be, you can't do it without a computer these days."