You have the ability to invest some of the money that you would have paid in taxes to add to your retirement fund. Many employers will offer the opportunity to defer a portion of your earnings and contribute them directly to your retirement account. Some of them may even match a portion of your savings. If this is the case, it is always advisable to save at least the amount that your employer will match. This will give you an automatic 100% gain on your money.
If you are self-employed, look into getting a Keogh, SIMPLE or a SEP IRA.