This week Democrats on the House Ways and Means Committee voted to advance dozens of proposed tax changes. Some are tax increases that would raise more than $2 trillion of revenue to help fund the party’s priorities.

The final shape of the bill and the fate of specific provisions are far from clear. Democrats have a slim majority in the House and a slimmer one in the Senate, while Republicans are almost uniformly opposed to the changes. Further wrangling could come on the House floor, and then the Senate gets its shot.

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This week Democrats on the House Ways and Means Committee voted to advance dozens of proposed tax changes. Some are tax increases that would raise more than $2 trillion of revenue to help fund the party’s priorities.

The final shape of the bill and the fate of specific provisions are far from clear. Democrats have a slim majority in the House and a slimmer one in the Senate, while Republicans are almost uniformly opposed to the changes. Further wrangling could come on the House floor, and then the Senate gets its shot.

As a result, key provisions not in the current version—such as an expanded deduction for state and local taxes (SALT), or required reporting of taxpayer bank-account information to the Internal Revenue Service—could still surface.

This much is clear: Once a proposal is “in play,” especially if there’s legislative language and a revenue estimate, its chances of passage grow. Even if it fails in the short run, it could re-emerge in the future.

It’s also unlikely that effective dates will be earlier than those listed in the bill, which for many provisions is Jan. 1, 2022. A notable exception are higher top rates on long-term capital gains, which would apply as of Sept. 13, 2021.

The Ways and Means provisions would raise the top rate on these gains to 28.8%, from 23.8%, for married joint filers with taxable income above $450,000 and single filers above $400,000. There would also be a 3-percentage-point surcharge for many filers with adjusted gross income above $5 million starting in 2022.

Warning: The new $450,000 and $400,000 thresholds are much lower than the current ones of about $502,000 for joint filers and $446,000 for single filers. The provision would apply to investors with one-time windfalls, such as a couple selling a home with a large taxable gain, as well as to taxpayers who are typically high earners.

While it will be hard for taxpayers to strategize for higher capital-gains rates, the 2022 start dates for other tax increases provide room for planning. Here are moves for a range of taxpayers to consider.

Accelerate ordinary income

Higher earners may want to pull some of next year’s income into this year to avoid higher rates proposed for 2022.

The Ways and Means provision would raise the top rate on ordinary income like wages or bonuses to 39.6% from 37%. Like the increase in the capital-gains rate, the change would apply above $450,000 of taxable income for joint filers and $400,000 for single filers. These brackets also kick in well below the current top rate, which begins at about $628,000 for joint filers and $524,000 for single filers.

Dustin Stamper, who monitors national tax developments at Grant Thornton, notes that the lower thresholds of the Ways and Means proposals could mean some filers who aren’t in the top bracket this year will be next year. For example, a married couple with $500,000 of taxable income would have a top rate of 35% for 2020—but 39.6% for 2022.

A new limit would also apply to the 199A deduction for pass-through business owners. This break allows sole proprietors and owners of partnerships, S corporations and similar entities to take a deduction of up to 20% of business income reported on their personal returns.

The proposed limit sets the maximum deduction at $500,000 for joint returns and $400,000 for single filers starting next year—so high-earning business owners might benefit from accelerating income into 2021.

Defer deductions

If top tax rates rise next year, tax deductions would likely be more valuable to those with higher rates. Mr. Stamper suggests considering whether to postpone deductions for charitable donations, deductible medical expenses and—especially—state and local taxes into next year.

If Congress expands the SALT limit of $10,000 per return, SALT payments that aren’t deductible this year might be allowed next year.

Make Roth IRA conversions—in some cases

Several Ways and Means proposals would impose new limits on saving in retirement accounts, starting in 2022. One would force payouts from accounts over $10 million—but most savers won’t face this issue.

Another would limit Roth IRA conversions to joint filers with $450,000 or less of taxable income and single filers with $400,000 or less. In a Roth conversion, a saver typically transfers assets from a traditional IRA to a Roth IRA and pays income tax on the switch. In return, payouts from the Roth IRA can be tax-free and often there are no required withdrawals during the owner’s life—unlike with traditional IRAs.

Yet the proposed limit wouldn’t take effect until 2032—so even very high-earning taxpayers have time to do Roth conversions.

“Congress still wants the conversion taxes from high earners, so they delayed the effective date for 10 years,” says IRA specialist Ed Slott.

However, another provision would prohibit savers with traditional IRAs and workplace plans like 401(k)s from switching after-tax savings in these accounts to Roth IRAs. Savers doing these “backdoor” conversions may want to maximize them this year, as it could be the last year to do so.

Do cryptocurrency wash sales

The tax law allows investors to use capital losses from their duds to offset capital gains on winners. Unless, that is, they incur a “wash sale” by purchasing the same asset 30 days before or after the sale. In that case, the tax break is reduced.

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The wash-sale rules don’t apply to cryptocurrencies under current law. So crypto investors have been free to sell losers, repurchase them immediately, and use the losses to offset capital gains (plus $3,000 of ordinary income like wages). The provision would extend the wash-sale rules to cryptocurrencies and other digital assets, and to commodities and currencies as well, beginning in 2022.

Jordan Bass, a CPA and attorney with Taxing Cryptocurrency, is advising clients to sell crypto losers before year-end. “That way they can still repurchase if they want to without triggering wash sales,” he says.

Give money away

Another provision would drop the lifetime gift-and-estate-tax exemption to about $6 million per individual, indexed for inflation, compared with this year’s exemption of $11.7 million.

The provision would take effect in 2022. Estate planners are reminding affected clients they can use this year’s $11.7 million exemption to give money to heirs (or trusts for them) without fear it will be clawed back if the exemption drops.

Ed Zollars, a CPA with Kaplan Financial Education who teaches tax professionals about changes in the law, notes that people who die in 2021 also won’t be affected if the exemption shrinks.

But dying, he says, is “not a popular strategy with clients.”

Write to Laura Saunders at laura.saunders@wsj.com