In the past, the collection of Post Office Openings was a popular area of collection. This has waned down over the years due to the difficulty in obtaining information on new openings. It is only by chance that covers are made nowadays.
Some actually collect post office closure covers. There is one coming up on 28 March 2016 at Carrefour Johor Bahru. If you are interested, the address is:
Lot 138, Batu 7 1/2, Jalan Kota Tinggi, Pandan, 81100 Johor Bharu
How to make a closure cover? Just paste a stamp on a blank envelope and get that cancelled with the last day of operations cancellation. It is the cancellation that you are after. Pretty straightforward and simple.
Please note, postal services will stop at 06:00 pm.
As with everything related to Pos Malaysia, it is always subjected to changes.
I think it will be beneficial to share information on such openings and closures. If you have any information in your area, just drop me a note and I will publish it. You can also make covers on behalf of anyone interested.