Next to losing weight, one of the most popular New Year's resolutions is whipping finances into shape. And it's not much different than a diet: you need to learn to balance what you take in versus what you burn, which in this case is money.

Jean Chatzky, with MSNBC & NBC's Today Show said the first step is to learn from your mistakes and try not to repeat them.

"Before you move forward, you have to look back, especially if you spent the bulk of 2007 feeling strapped for cash. If you didn't have the foresight to track your spending at some point during the last year, you can still get a general idea of where your money went by looking at your bank and credit card statements," she said, in an article on MSNBC.

"One of the important things when looking back is to be able to classify which expenses are fixed and which are variable," added Sabrina Lowell, a financial planner with Mosaic Financial Partners in San Francisco.

Fixed expenses are defined as nonnegotiable, like a mortgage, monthly bills for water, heat and utilities, as well as insurance. Variable expenses are things like vacations, new clothing, dining out and other entertainment costs.

It's not good advice to try and cut out all the variable costs, but definately helpful to track them and learn to utilize some willpower when setting personal goals and spending limits.

Identify priorities

"Make a policy of how much can be spent, and how frequently that expense can be incurred. Then the decision to open your wallet becomes really easy: Does it fit into your policy or not?" Be honest, Lowell said in the MSNBC article.

Ignore bonus money

If you got an end-of-the year bonus at work, or get more than you expected from your tax return, don't spend it, save it.

"When you get a bonus, put it into savings. When you get a raise, bump up your 401(k) contribution. If you pay yourself first, you're going to reach your savings goals," Mark Stinson, a financial planner at Baltimore-Washington Financial Advisors, said in the Chatzky article. Remember that this is money you won't miss, because you're already accustomed to your old salary and lifestyle. And if you have debt, it's a good idea to use any additional income to pay it down.

Boost your earnings

Chatzky said your income needs to at least cover your fixed expenses, plus any surprises that may come your way. If it doesn't, you need to look into either finding another job, upping your hours, or taking on an additional part-time job.

Hold yourself accountable

Chatzky said there are any number of programs now that allow you to track your spending, so you won't have to sort through credit card statements and crumpled receipts next year. Quicken will automatically show you where your money is going. At about $30 for the starter program, it's relatively inexpensive, too. But there are also free programs popping up all over the Web that work in the same way.

The two most popular, Wesabe (wesabe.com) and Geezeo (geezeo.com), will show you your bank account and credit card balances, as well as how much you're spending on everything from food to entertainment to personal grooming. Click here for more financial advice from Jean Chatzky

An Excel spreadsheet is also an easy standby for people who want to keep things simple while tracking their finances.

the bottom line? Find a system that works for you, because in the age of debit cards and ATM machines, it's way too easy to lose sight of how you're spending your hard-earned dollar, Chatzky said.