You should use rich soil and a balanced NPK fertilizer but supplement it with additional N and add calcium.
This promotes good, fast growth, but leaf size is a matter of the strain of coriander and especially the temperature. In many regions it is considered a spring and fall crop because once temperatures get above about 75F and the plant has matured a few weeks (at most), it will bolt and produce much different looking thin lobed leaves.
If you're growing it for the cilantro leaves, not the coriander seeds, then your best bet is having a lot of grow area. Rather than trying to get each plant large for more leaves, you want more plants in total, but you don't want them spaced so closely together that more energy is put into stem length.
When harvesting leaves, thin each plant such that leaves aren't overlapping each other as much. This tends to mean pick them from the middle, not the ones hanging out on the edge which are a quick lazy way to get some to use, but will make the plant produce more stem to (lower) leaf ratio.
As far as watering goes, if they are in pots, try not to water enough that any water runs out the bottom of the pots. If they are in the ground, try to resist watering until they show signs of droop, then give that soil a good 1" X area water volume as a start, then adjust to more water at a time if you find that you have to water more often than once every two days.
When watering, try to avoid getting the leaves wet as they are thin, delicate leaves and water can easily cause magnified sun damage. Also avoid foliar feeding since that makes it all the more of a hassle to rinse the leaves sufficiently prior to consumption, as they are easily bruised in handling.