(MONEY Magazine) – Now that you've mailed in your 1994 tax return, you'd probably like to take a well-deserved spring break from deductions, exemptions, depreciation and the general depression of grappling with the tax code. But don't bury that copy of your 1040 in a drawer just yet. Last year's filing may be history, but you aren't condemned to repeat it. As we've suggested before (see our April 1992 issue), this is the perfect time to learn from your return.

First of all, it's quite possible you'll find errors or deductions you might have missed the first time around. You usually have three years to amend your return using the one-sheet Form 1040X. But don't delay-you'll owe the Internal Revenue Service interest on tax due or will miss the chance to earn interest on a refund.

Looking ahead, I guarantee you'll spot potential tax savings for 1995 everywhere on the Form 1040 and its schedules. To get you started, I've listed several of the more common problems you might discover, along with tips on how you can turn 1994's regrets into 1995's tax savings.

-- My charitable contributions were skimpy. Here's one area of your return (Schedule A, line 18, to be exact) that's easy to beef up: You can donate as much as 50% of your adjusted gross income (AGI) to charity and deduct every penny. If you're short on cash, consider donating stocks, paintings, even used clothing and household goods instead. In fact, giving away appreciated property, such as stock, can bestow a double tax blessing (when you hand it to a charitable organization other than a private foundation). You deduct the fair market value of the asset on the date of the gift and avoid the capital-gains tax on its appreciation. A $1,000 donation of either cash or stock gives you a $1,000 write-off. But if you paid only $400 for the stock, you also forever avoid tax on your $600 paper profit. That could save you $168 in capital-gains tax ($600 times the 28% top capital-gains rate) in addition to the $310 the $1,000 donation is worth to filers who are in the 31% federal bracket.

-- I couldn't claim all of my investment losses. After a year like 1994, when the bond market tanked and stocks barely budged, you may have fumed over big investment setbacks. Then you got mad all over again when you learned that you couldn't deduct all your losses. Generally, you can claim only $3,000 in net capital losses in one year (Schedule D, line 19B); anything over that amount must be carried over to the following year. But the key word here is net. If you have capital gains, you can use the losses to offset them. Of course, you don't want to make investment decisions solely to produce tax benefits; but if you find yourself taking losses as 1995 wears on, look over your portfolio to see if it makes sense to sell any winners so that you can make full use of your deductions. For example, if you have $5,000 in stock losses, create a $2,000 profit by selling other more successful investments. Your $3,000 net loss will be deductible in 1995, and you'll receive the full benefit of your $5,000 loss. If you want to keep your winners, you can repurchase the stock immediately.

-- My capital gains were much too high. Maybe you beat the odds last year and piled up profits on stocks and bonds. Well, the advice in the previous paragraph also applies to lucky you. You can offset your taxable gains by taking some losses (again remembering not to let tax strategy dictate investment decisions). If you have $4,000 in capital gains, create $4,000 in losses and save $1,120 in taxes ($4,000 times 28%). Or let's say you have no losers (lucky you, again), but you are selling only a portion of a profitable investment position that you accumulated over time. In that case, you can cut your taxable gains by telling your broker or mutual fund in writing that you want to sell only the shares for which you paid the highest prices. A word of warning, however: You must wait at least 31 days to buy back the same stock, or your loss will not be deductible.

-- Poor record keeping cost me a bundle. Nickel-and-dime forgetfulness can cost you big bucks in several places on your tax return. If you're an employee, look at Form 2106, where you missed out if you didn't keep careful track of deductible cash business expenses such as buying gas for your car. Then there's Schedule A, where you may have forgotten to note casual cash donations, such as the $5 you gave to the Salvation Army Santa. Or there's Form 2119, where you keep track of home improvement expenses that could slash your capital gain when you sell. Don't just regret bad habits, change them today. Never make deductibility decisions at the cash register. Always ask for a receipt when using cash and keep every receipt, credit-card slip, and restaurant stub until you're sure you can't use it.

-- I didn't put enough into my pension plan. If lines 23A and 23B on your 1040 were blank, you may have missed a big tax break. That's where you enter contributions to Individual Retirement Accounts. You and your working spouse can put as much as $4,000 into an IRA ($2,250 if only one of you has a job)-and deduct the full amount if you don't have a pension plan at work. If your employer offers a pension plan, your deduction phases out between adjusted gross incomes of $40,000 and $50,000 on a joint return ($25,000 and $35,000 for single filers). If you're self-employed, give as much as 20% of your net earnings to a Keogh plan or 13.0435% to a SEP-IRA, up to a maximum of $30,000 for either plan. But perhaps the best deal of all is your employer's 401(k) plan. For one thing, the money you salt away in a 401(k) reduces your taxable income; in 1995, the maximum contribution is $9,240, which would save you $2,864 in taxes in the 31% bracket. Plus, many employers will match some or all of your contribution.

-- I just missed being able to itemize. If your itemized deductions for 1994 (Schedule A, line 29) came close to but did not top the standard deduction given to all taxpayers, consider "bunching" your deductions to clear the 1995 hurdles ($6,550 for joint filers, $3,900 for single filers and $5,750 for heads of households). Make two years' worth of charitable contributions in 1995, prepay an extra installment of property taxes and make your fourth-quarter state estimated tax payment by Dec. 31. Apply the same strategy to medical expenses (Schedule A, line 3), which are deductible only to the extent they exceed 7.5% of your AGI. Schedule orthodontic work, purchase prescription drugs or get a checkup. To top the 2% of AGI threshold for miscellaneous itemized deductions (Schedule A, line 25), buy extra business equipment or investment-related items such as financial advice books and software.

-- I didn't compare filing jointly vs. filing separately. For working couples, filing separately can pay off when one partner has a small income and very high medical expenses or unreimbursed employee business expenses. Reason: The individual with the smaller income is more likely to surpass the thresholds for those deductions (noted above). Unfortunately, the only way to find out is to compute your taxes both ways. If you filed separately in 1994 and learn that filing jointly would have saved you money, you can amend your return using Form 1040X. But if you filed jointly, you're stuck: You can't change to separate returns. Just be sure you check both ways before filing this year's taxes.

-- My self-employment taxes were staggering. One disadvantage of being self-employed is that you're both employer and employee when it comes to paying Social Security and Medicare taxes (computed on Schedule SE), which can gobble 14.13% of your net business earnings. To shrink the tax bite, lower your earnings. No, we don't want you to turn away customers. But you can stock up on needed equipment and office furnishings late this year instead of early next year, for example. And you can sign up for courses related to your work, donate inventory to charity and borrow money for purchases such as office space. The value of these maneuvers will depend on whether your earnings are above or below the $61,200 ceiling on Social Security tax. If you bring your net earnings down from $60,000 to $50,000, you'll save $1,413 in Social Security and Medicare taxes. If you reduce net earnings of $80,000 to $70,000, however, your only savings will be $268 on Medicare taxes. You'll have no savings on Social Security tax because both your "before" and "after" net earnings exceed the $61,200 ceiling.

Careful analysis should uncover even more ways to cut your 1995 taxes. Look at your 1994 return as nothing more than a rough draft of that ideal return you could file someday-where no income is needlessly taxed, no credit goes unclaimed, and every deduction has been run to earth.