do not add too much spices and masala .it will spoil the taste of the biriyani.
add chili as per the heat level.
depends on the quality of rice you may need more or less water.always keep some boiled water aside so that you can add this to rice if needed,
cook meat first ,then cook rice
if you are using pressure cooker for making masala cook the marinated meat first.add little water approximately 2-3 whistle.then completely evaporate excess water.add this meat to the masala.
you can cook rice also in pressure cooker,keep water level on inch above.for jeerakasala rice 1 whistle is enough.let the pressure goes naturally.