Define small widgets

Do

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Column(
      children: const [
        Widget(),
        Widget(),
        Widget()
      ]
    )
  );
}

Don't

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Column(
      children: const [
        Row(
          children: const [
            Text(),
            Text()
          ]
        ),
        Padding(
          padding: EdgeInsets.all(16.0),
          child: Column(
            children: [
              Row(
                children: const [
                  Text(),
                  Text()
                ]
              ),
              Text()
            ]
          )
        )
      ]
    )
  );
}

Conclusion: Leads to code that is more readable and easier to reason about.