By Lorna Tan, Finance Correspondent

Tax time is here again for individuals - just as other money worries are crowding in for many people.

But there is no need to fret. The process of submitting tax returns in Singapore is one of the simplest in the world, especially if you keep a few basic principles in mind.

Also, there are enhanced incentives about to come into effect which are designed to encourage taxpayers to admit past mistakes to the taxman.

First the basics: If you are submitting a hard copy, the tax form must be posted to the Inland Revenue Authority of Singapore (Iras) by April 15.

Online filing is fast gaining popularity. Those filing their returns on the Internet have an additional three days to do so. Their deadline is April 18.

Every tax return should be completed with care but some groups come in for particular scrutiny from Iras in a given year.

Iras makes an ongoing effort to identify industries it can help with education programmes - such as proper record-keeping methods.

Last year, real estate and food and beverage operators were in the spotlight.

This year and the next, three self-employed groups can expect close scrutiny so they should exercise extra care when filing returns.

They are: medical practitioners, renovation contractors and public accounting firms. Iras will be checking the details of their income declarations and verifying them against documents and records.

The inclusion of medical practitioners is partly due to the rising popularity and prominence of the Traditional Chinese Medicine (TCM) sector in recent years. Last year, Iras organised two seminars for 170 TCM practitioners to help them with the submission of tax returns.

Although tax time comes around every year, individual taxpayers still tend to make common mistakes - often involving the reporting of rental income and claims for parent relief.

Here are some basic principles taxpayers should look out for:

Rental income

Among taxpayers who rent out property, it is a common mistake not to report the gross rental income that they collect.

In most cases that fail to meet Iras' requirements, taxpayers omit the income they get for furniture and fittings. The taxman says taxpayers need to declare the gross or total figure - which typically includes rent for premises, furniture and fittings, and service charges.

You can claim interest on your mortgage loan but mortgage interest incurred on personal loans is disallowed. Other tax-deductible expenses are property tax, fire insurance, commission paid to secure a subsequent tenant - commission paid to secure a first tenant is not tax-deductible - and expenses on repairs and maintenance.

• Case 1: Incorrect reporting of rental income

• Mr and Mrs Chia are new owners of a private apartment which they are renting out. Mr Chia approached Iras to admit that in their declaration of the rental income for the first year, they omitted to report the rental income received for furniture and fittings.

• In addition, they wrongly claimed the agent's commission for getting the first tenant, and the cost of buying furniture for the apartment, as expenses.

• The outcome: Iras adjusted the rental income to include the rental income received for furniture and fittings, and disallowed the expenses on the agent's commission and the cost of the furniture.