NEW YORK (MarketWatch) -- Though the tax season is past us, some people must continue to pay taxes year round: the self-employed. For them, tax planning never stops. Without a regular pay check, they have responsibility for their own tax tactics.

If you are in this situation, you can save yourself time and money with these four tips:

1. Educate yourself on the self-employment tax. The surest way to save on your bill at year's end is to fully understand the tax laws that apply to you. The best resource is the Internal Revenue's website, IRS.gov.
2. Consider computerizing your record-keeping. Record-keeping is essential for accurately estimating your quarterly payments and for filing your end-of-the-year tax return. If you have not done so yet, consider buying a software program to keep your finances organized. Two popular programs for sole proprietors are Microsoft Money Plus and Intuit Quicken Home and Business 2008.
3. Make your estimated payments on time. Unlike salaried employees, the self-employed have no income withheld from their paycheck. They must estimate their income minus deductions and pay tax on these estimates four times a year -- the 15th day of April, June, September and January (of the next year). By paying on time, you avoid late penalties.
4. Establish a retirement plan. Contributions to certain kinds of plans can be deducted from your tax bill. Consider a Keogh retirement plan if your business has employees. To qualify for deduction for the current year, you must open a Keogh plan before Dec. 31.You can refer to IRS Pub 560 for more information on retirement plans, including Keogh plans, for the self-employed.