Are you looking for shoaling or schooling fish, there is a big difference. Shoaling is a group of fish that will hang together. Schooling is a swimming pattern of a group of fish that is coordinated and directional.
Shoaling can easily accomplished with cardinals. Lookdowns will swim together as well as pilotfish and pompano in a tanks but it is not schooling.
Schooling is much more difficult. With much effort, I have come to the conclusion that a predator must be present for schooling behavior to persist or a strong rotational current forcing directional swimming in a round aquaria (I call the latter pseudo-schooling). I have worked with fish like menhaden and silversides - these fish spend their lives swimming in schools. Hours to days after being removed from the ocean and place into a pool the schooling behavior ceases. When I've added a predator like a shark - the fish instantly group and start schooling. My point is that - attempting to create a school of fish in your tank without the addition of something that is going to eat those fish will be fruitless.