Fried fish goes soft within hours and doesn't keep. Slaw keeps 2 days dressed and is arguably better on day two. Cook the fish fresh; everything else preps ahead.
This uses a light flour dusting, which is quicker and lighter. A beer batter is crispier and more substantial but needs deeper oil and more effort.
Flipping too early or too often, or using a very flaky fish like sole. Let a crust form and use one confident turn.
Two to three. A pound of fish comfortably fills 8 tacos — four people at two each.