In the context of a fullstack web application here is the workflow I'd like to have for a great DX.
1.1 Start from the UI, build it screen by screen in isolation with something like storybook/react-cosmos.
1.2 For a screen, write your data needs in term of graphql queries, mutations and/or subscriptions.
1.3 If you use a strongly typed language (like Purescript or Reason) it should be able to fail at compile time because schema's types are missing. For JS, the tools (cli, vscode extension...) should be able to point the undefined types, queries, mutations and subscriptions (if you use SDL in gql tag for example).