1 - FRIENDS - If you are going to be working in Malaysia you will have no problem as you will make friends at work.
If you are a trailing spouse like I was, it is important to join as many associations as possible (you can join British/American/Australian Association, Womens Association of Malaysia and classes (I joined a jewellery making class in Sri Hartamas which I really enjoyed and art classes). Mixed martial arts classes are very good in Taman Danau Desa. There are lots of voluntary opportunities working in childrens homes, etc.. Make sure you have one activity to go to every day of the week Mon-Fri when your husband/wife is at work, if you don't do this you could end up feeling isolated or homesick. Number 1 is the most important tip of all, because it is crucial to make friends if you are to have a successful transition to living somewhere new...If you are not prepared to do this, then you may aswel stay where you are already.
2 - TRAVEL - Traffic can be a NIGHTMARE in rush hour. Live AS CLOSE TO WORK AS POSSIBLE, a 15 minute drive in KL with no traffic could take me an hour on a weekday or an hour and 20 mins when it is Ramadan. Choose where you are going to live VERY VERY WISELY !!!
3 - SAFETY - Be careful not to dress too flashy, - expensive jewellery etc.... Don't carry a handbag when out on your own in the day time around the shops. If you follow this advice you will not attract undue attention and will not be a target for bag/jewellery snatchers.
Take extra care when parking in secluded and dark carparks, always park in the woman only designated parking bays in multi storys. If you take public transport be very aware. Do not get in the front seat of a taxi, even if the driver says his back door is not working.
4 - MOSQUITOS/SNAKES - Dengue fever - you do not want to catch this, take precautions to cover your arms and legs with long clothing and spray with insect repellant. If you live in a house like I did be on your guard for snakes, we had a large number of baby cobras in our garden.
5 - INTERACT WITH THE LOCAL PEOPLE - Take the opportunity to broaden your outlook by getting to know people of a different ethnicity and culture than yourself. Take the time to get to know the local people, Malyasians are lovely people, don't segregate yourself with just people of the same nationality as yourself. Familiarise yourself with local customs and be respectful to their ways, if you are brave enough learn the language ! Don't be offended by intrusive questions or blunt observations I have found that this seems to be acceptable in a couple of places that I have lived in Asia.
If you follow my 5 tips you should not go far wrong, and should have a fabulous time in Malaysia !!!