One thing Anthropic did that I loved and think was very smart was building a prompt generator[1] into the developer console. The generator is tuned to generate prompts the way Claude prompts are supposed to be, which improves responses. And you can use it to improve your user prompt as well, not just your system prompt, which make responses even better.

You can see examples of the prompts it generates here[2]. It significantly improved my experience with LLMs; I haven't touched GPT4 in quite a while, and GPT4o didn't change that.

[1]: https://docs.anthropic.com/en/docs/build-with-claude/prompt-...

[2]: https://sr.ht/~jamesponddotco/llm-prompts/