Starting to put money aside toward retirement early in your life helps you build a big retirement nest egg. But if you've waited until your 50s to start thinking about saving for retirement, you're not doomed to a miserable retirement. By taking advantage of some special provisions that only apply to older workers, you can turbocharge your retirement savings when you need it most.

If you're in this group, you're not alone. According to a recent survey from the Employee Benefit Research Institute, more than half of all those 55 and older have saved less than $100,000 toward retirement, and a quarter have saved less than $10,000.

But don't despair. Here are several tips to get you building your retirement savings in a hurry.

1. Catch up on your retirement contributions
Using a combination of IRAs and your 401(k) plan at work can help you build savings in a hurry. With limits of $5,000 on IRAs and $15,500 on 401(k) contributions for 2008, you can save more than $1,700 every month with big tax advantages.

Yet those over 50 can contribute even more, thanks to so-called "catch-up" provisions. To give older workers more opportunity to save, the catch-up provisions allow those age 50 or older to contribute an extra $1,000 to an IRA, and $5,000 more to a 401(k) plan.

2. Be aggressive
Most financial planners recommend that retirement investors get more conservative with their investments as they age. For instance, Fidelity's target retirement fund for those planning to retire in 2020 has only 65% of its assets allocated to stocks, with the rest in more conservative income-producing securities. In addition, a big part of that 65% will be in huge names such as Wal-Mart (NYSE: WMT) and Intel (Nasdaq: INTC) -- companies whose best opportunities for explosive growth are behind them.

To help you catch up, you should consider a more aggressive stock portfolio. Although this exposes you to significantly more risk, you may feel comfortable with that risk if you need high returns in order to achieve your goals. One area that you should consider is small-cap stocks, which have had some great returns in recent years. Here are a few examples:

Stock

5-Year Annualized Return

Nuance Communications (Nasdaq: NUAN)

32.1%

Ctrip.com (Nasdaq: CTRP)

57.5%*

Middleby (Nasdaq: MIDD)

60.1%

Hansen Natural (Nasdaq: HANS)

131.2%

Stillwater Mining (NYSE: SWC)

44%

*Ctrip.com returns calculated from IPO on Dec. 9, 2003.

Don't be fooled -- not every stock goes up like this, so investing in small-cap stocks is far from a risk-free proposition. But if your risk tolerance is high, using aggressive investing strategies like this one can help you close the gap after a late start.

3. Cut your costs
Finally, you can take steps to get by with less money. Many retirees downsize to a smaller home or relocate to less expensive areas to make their money go further.

In addition, reducing expenses before you retire has a double benefit. Not only will you get used to living on less, but you'll also be able to put more aside toward retirement savings. That'll make those catch-up contributions easier to make.

Whatever you do, don't give up. It's never too late to start planning for your retirement.

To learn more about building a great retirement, read: