How to Write Effective Custom Instructions in ChatGPT

Custom instructions are two boxes in Settings that apply to every new chat: one about you, and one about how you want ChatGPT to respond. Filling them in well saves you from repeating context like your job or your preferred answer length. This guide shows what to put where for the biggest payoff.

What you need

• A ChatGPT account
• A sense of how you usually want answers (length, tone, format)
• Three minutes

Step 1: Open custom instructions

Go to Settings, then Personalization, then Custom instructions. You will see fields for what ChatGPT should know about you and how it should respond.

Step 2: Describe who you are and your context

In the first box give the stable facts that change how answers should be pitched: your role, your skill level in relevant areas, and what you typically work on. This is context, not a task list.

I'm a marketing manager at a small B2B software company.
I'm comfortable with spreadsheets but not code.
Most of my questions are about copywriting, analytics, and campaign planning.
I write for a non-technical business audience.

Step 3: Specify how you want responses

The second box is where format preferences live. Be concrete: length, structure, tone, and what to avoid. These are the rules that otherwise eat the first line of every prompt.

Be concise and lead with the answer, then the reasoning.
Use short paragraphs and bullet points over walls of text.
Avoid hype words and filler. Plain, direct English.
When you make assumptions, state them in one line at the end.
If a request is ambiguous, ask one clarifying question first.

Result

Every new chat now starts knowing your role and answer preferences, so responses come back at the right level and in your preferred format without a setup paragraph each time.