Coriander, also commonly called cilantro should be always grown from seed, directly in its permanent growing place. It hates to be transplanted and the stress will likely cause it to go straight to seed and then it dies. And you never get any leaves at all! Also, coriander grows a big taproot, and those little seedling pots are not deep enough to accommodate it. Pre-growing it in a pot isn't doing it any good, so don't bother buying cilantro from a nursery in a pot. Just get the seed.
Coriander doesn't like two things: humidity and heat. Anything that stresses them, will cause them to bolt. So, in a tropical climate like Singapore, it should be started and grown during the cooler season, choosing the spot with full sun and where air can circulate freely. If you expect hot weather, give coriander some shade. Best to plant seeds in a dark, rich soil, as it produces the biggest, healthiest plants, but any reasonable soil with average nutrient levels should be fine. If you want to feed your plants extra, some dilute liquid fertilizer like fish emulsion never goes astray.
Sowing seeds at 1cm deep and about 5cm between the plants. Cover the seeds with an extra layer of soil and keep them moist. Keeping coriander well watered and using a well draining soil is very important. Germination takes about 2-3 weeks to germinate. If they come up too thickly, just pull up the extras, so there's enough room for them to grow.
Sooner or later your coriander plants will flower. Once they start developing that flower stalk they stop making more leaves. Therefore it is a good idea to re-sow cilantro every few weeks during the growing season. That way you never run out.
The fabulous thing about the coriander seeds is that they don't rot over the wet season like the seeds of many other annuals do. Coriander seeds just site there, through the heat, the torrential downpours, months of steamy soggy weather, and they wait. They wait until the next dry season comes around. And as soon as you get the first crisp nights, new cilantro plants pop up all over your garden!