Shoes are commonly left at the front door of houses and some other buildings. A collection of shoes at the door is a giveaway that you may have to remove your shoes. Another sign is if you notice you are the only one wearing shoes!
Many Malaysians greet each other with a less than firm handshake and may then place their right hand over their heart after greeting you. Watch what happens and follow their lead.
In the city, the presentation of business cards or name cards often follow an introduction as a sign of interest in keeping contact with you, either socially or for business purposes. It is actually your prerogative; so use your discretion if it is wise to give your card or kindly excuse yourself for not carrying any of your own. But in doing business, it is a common practice though not compulsory.
Physical signs of affection in public are frowned upon and on the East Coast of Malaysia, men and women keep a safe distance from each other in public.
There are certain areas of mosques that should not be entered by non-Moslems. Signs are often displayed or people will inform you. Conservative dress is always required in all parts of mosques.
Many older people are simply referred to as "uncle" (pakcik) or "aunty" (makcik). People younger than you may also address you with such a term - take it as a compliment. Many people bow their heads as they walk past people, especially older folk.
Some Malaysians eat with their hand. In many restaurants this is more than acceptable and well worth trying (saves waiting for the cutlery!). A tip though - only use the right hand as the left is used for more basic bodily functions.
If invited to a Malaysian home, the host will be most appreciative if you come bearing gifts, though this is not a must. Whatever you choose to bring - be it a souvenir from back home, some fruits or drinks purchased from a store around the corner - rest assured it would be welcomed sincerely. Even amongst Malaysians themselves, this practice is observed. Bringing a gift is known as carrying buah tangan, which literally means "fruit of the hands".
Many Malaysians are superstitious and there is a fascination with lucky numbers (essential for buying favourable numbers in lottery draws). Ask a Malaysian to explain this interest or when they jot down car license numbers at the scene of an accident.
There is a Chinese word called "kiasu". The English translation means something like "the fear of missing out". This surfaces in many situations - drivers being aggressive on the road, wearing branded clothes and accessories, using mobile phones loudly and piling one's plate the highest at a buffet. What does it all mean? It's about keeping up with the Jones's, it's about, "I'm as good as you", etc. This doesn't mean expats have to be kiasu, but being aware of its presence will help you understand many situations.
As in many Asian countries, Malaysians don't often show anger in public. When others do, many Malaysians are unsure of what to do next. Remain calm, firm and avoid shouting when things do not go your way. Something may be resolved if you are calm, but nothing will be achieved through ranting and raving.
Many Malaysians do not want to disappoint foreigners so a "yes" may not actually be in the affirmative. If you need a definite answer you might try and talk around a topic for awhile until you determine whether it is a real "yes" or a "no-yes".
This has a lot to do with "face". Face is another difficult concept to explain but most Malaysians do not like to "lose face" - i.e., they do not want to give the wrong information or to be caught out, no matter what. You can "give face" by being understanding if something goes wrong; by not reminding people of this, by compensating for small mistakes and/or by not making a public spectacle. A difficult one, but very important for surviving in many Asian countries. Try and be a little humble - be honest about your faults and modest about your achievements.