What tackle to use
8 - 10 wt outfits. 300 m of backing as a minimum, large diameter fly reel, 10 - 12ft leader length, tapering to fluoro tippets of 14 - 20lb.
What flies to use
Shrimp fly; Bread fly; Scum or Weed fly; Salty BMS; Small Clousers
The hardest part is getting the fish to eat your fly and in some parts of the country some anglers use bread berley and cast bread fly imitations into where the fish are feeding, however this is not everyone's approach. They eat algae scum and small marine organisms so a more 'purist' yet challenging approach would be tiny flies to match the hatch.
Milkfish are not carnivorous predators and don't chase down their prey, rather they Bread berley and bread fly is a popular method. A lot of progress has been made sight-fishing fishing to active schools in very warm water using small shrimp flies.
Luck, persistence, patience, the correct conditions, feeding fish and weather all play a part in being able to target them.