The Washington Post's annual tax guide is a step-by-step aid to preparing your federal, District of Columbia, Maryland and Virginia taxes and dealing with recent tax law changes. The guide was compiled by Jeffery P. Capron, a certified public accountant and a partner at McQuade and Capron, an accounting firm with offices in Washington and McLean. He was assisted by Richard H. Lee and Salvatore M. Ambrosino of the firm.

A LULL IN MAJOR TAX CODE CHANGES

Entering this tax filing season, taxpayers and preparers have another annual new tax law to contend with. Although most of the changes in the new law won't take effect until filing season next year, there are some differences, especially for military personnel affected by the Persian Gulf War. Page 5

DO IT YOURSELF?

Many taxpayers should be able to do their own returns, especially those with straightforward financial situations. There are several sources of information for those who need help. If you decide to use a professional preparer, choose carefully. Page 7

BASIC FILING RULES

Some individuals are not required to file a return. The threshold is based on the sum of the taxpayer's personal exemption and standard deduction. Page 7

FILING STATUS

Your filing status depends on your marital status, household living arrangements and people dependent on you for support. Page 8

EXEMPTIONS

If you can't be claimed as a dependent by your parent or someone else, you are entitled to take a personal exemption for yourself. For 1990, each personal and dependency exemption is worth $2,050. Page 9

REPORTING INCOME

In reporting income, the focus should be on what income is taxable and what is not. Page 10

ADJUSTMENTS TO INCOME

Allowable adjustments for 1990 are the same as for 1989, except the new deduction for one-half of self-employment tax. Page 16

DEDUCTIONS

Many taxpayers find the standard deduction more advantageous than itemizing. However, taxpayers with a home mortgage or with substantial liabilities are likely to itemize. Which is the better way? Page 16 COMPUTING YOUR TAX

Should you use the tax table or tax rate schedule to determine your tax? Page 18

TAX CREDITS

You may be able to reduce your income tax significantly through the use of any of several tax credits. Page 18

OTHER TAXES

In addition to the taxes calculated from the tax table or tax rate schedule, you may be liable for additional taxes. Page 18

TAX PAYMENTS

If you've determined your total federal income tax liability for 1990, the next step is to apply against that liability tax payments you've already made. Page 21

THE BOTTOM LINE

Compare your total payments with the total tax. If your payments are larger, you may choose to have the overpayment refunded, applied to your 1991 tax or a combination of both. If the total tax is larger, the difference is the amount you owe. Page 21

DISTRICT

The District made only a slight changes in its tax system in 1990. The personal exemption and the low-income credit have been increased, and a new filing status, "dependent taxpayer," has been added to the tax form. Page 24

MARYLAND

Maryland made several changes in its law for 1990 returns. Among them: the personal exemption has been increased; the minimum filing requirements have been raised; and a new and simple form has been introduced for taxpayers from whom Maryland taxes have been withheld, but who otherwise are not required to file. Page 26 VIRGINIA Developments in the legislature and the courts have resulted in changes to the Virginia income tax return for 1990. Page 27