By now, your child's college financial aid letter has probably arrived, and likely left you confused and disappointed. Aid letters are notoriously hard to decipher, and in most cases there's a gap between a family's actual need and the money students are offered.

By now, your child's college financial aid letter has probably arrived, and likely left you confused and disappointed. Aid letters are notoriously hard to decipher, and in most cases there's a gap between a family's actual need and the money students are offered.

First, the letter. As a parent, you need to determine what is gift aid that doesn't need to be paid back, such as scholarships and grants, and what is a loan. Not all colleges make it clear.

"All letters are different, and with some you don't know if you got a good package because the aid office can plug in a parent loan at the end then say your out-of-pocket cost is nothing," even though that isn't true, said Paula Bishop, an independent financial aid consultant based in Seattle.

Her advice? First, know how much it costs a student like yours to attend the school. This is another area where the aid letter can be misleading: Some don't include the true cost to attend, which is tuition, fees, room and board, books and travel to and from school. Sit down with a calculator, figure out the true cost, then subtract the gift aid. That's how much you'll actually be paying for college. (For a list of questions to ask the financial aid office and more information about net price calculators, read this story from Edvisors.com, a website about paying for college: edvisors.com/fafsa/after-submitting/award-letter/#award-letters-can-be-confusing.)

Not sure your package is fair? Go online and use a net price calculator to find out what families similar to yours are paying to go to that school, Bishop said. Many colleges have their own calculators online, or try the College Board tools at netpricecalculator.collegeboard.org.

It's worth running the numbers, because "occasionally, the aid office does make an error," Bishop said. One of her clients did the math and realized their child had been underawarded. The financial aid office then corrected the mistake.

If you still aren't satisfied with the aid package, you can appeal and lobby for more money. Each school has its own policies and forms. Some schools - about 60 or so in the U.S., including the Ivy Leagues - don't offer appeals because they give only need-based aid, not merit-based aid. With those schools, you've already been offered everything you qualified for, so "Unless there was an error on your FAFSA, you aren't getting another dime," Bishop said.

Here's how to appeal. First, don't wait. Do it right away, because the pool of financial aid money is used up quickly, and you'll likely have to go back and forth with the aid office to negotiate several times. Second, you're most likely to get more if your family's financial life has changed drastically via either job loss, death or divorce.

If nothing has changed but you just can't stretch the dollars to cover the gap, you'll have to carefully make your case to the aid office. One student won more by writing - the student wrote it, not the parent - a letter outlining her love for the college, her work history and the specific amount she needed to make the numbers work.

Letters need to aim for the heart. First generation in college or in America? Escaping poverty or war? Say so. "If you can make the aid officer shed a tear (or feel something), you stand a chance," Bishop said. "If you just want more money and you're making $300,000 a year but don't want to spend it, forget it." That's the letter they'll pin on the bulletin board in the break room "and will laugh about every time they walk by."

Even if your appeal is successful, don't expect a miracle. Schools might throw another "$3,000 to 5,000 at you, or a bigger loan or more work study. It's not going to be $20,000. It's not going to be a game changer," she said. Why? Most of their money is already spent.

"Most give out merit money based on test scores or GPA, and they run out of that money quickly, so there isn't a lot left. They might have some left for need-based aid, but until they finalize all the financial award letters, they don't know how much. They hold onto that money," Bishop said.

Still can't make it work? It might be time to consider a school with a lower net price, according to Edvisors.com, such as an in-state public college or a college with a "no loans" financial aid policy.

-Denise Trowbridge is a self-professed money geek who writes about personal finance, banking and insurance for The Columbus Dispatch, bankrate.com and middlepathfinance.com.