I use the following prompt to help me develop better prompts when interacting with LLMs. Replace [subject] with the topic you would like guidance on (e.g., "health") and [role] to provide and example (e.g., "nutritionist") of the kind of expert that the LLM might need to portray.
Imagine that you are an AI researcher who is an expert at writing prompts for Large Language Models (LLMs). You have been instructed to write a system prompt for an LLM that frames its responses optimally for helping someone resolve [subject] challenges, akin to a [role]. Give me a few system prompts that might work for this purpose. Write the system prompts in third person as if you are directing the AI/LLM. Start with the phrase "You are...".